Not medically reviewed
Medical terminology: word parts and abbreviations
Not medically reviewed · Content last updated · 5 min read ·
This is the date the draft was written, not a medical review date.
Medical words are built from prefixes, combining roots and suffixes. Learn the parts and most terms can be decoded. Abbreviations are listed with their meanings; unsafe or ambiguous ones are flagged.
Search or filter the word parts and abbreviations below, or browse them by section and by letter. Every entry is listed on this page. Check unsafe or ambiguous abbreviations against your local policy.
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Medical prefixes, suffixes and combining roots
341 entries
Prefixes
| Word part | Meaning | Example |
|---|---|---|
| hyper- | above, excessive | hypertension: Persistently elevated arterial blood pressure. |
| hypo- | below, deficient | hypotension: Abnormally low arterial blood pressure. |
| a-/an- | without, absence of (an- before a vowel) | anaemia: Reduced haemoglobin or red cell mass. |
| anti- | against, opposing | antibiotic: Agent that kills or inhibits bacteria. |
| brady- | slow | bradycardia: Heart rate slower than normal (conventionally below 60/min in adults). |
| tachy- | fast, rapid | tachycardia: Heart rate faster than normal (conventionally above 100/min in adults). |
| dys- | bad, difficult, abnormal | dyspnoea: Subjective sensation of difficult breathing. |
| eu- | good, normal, well | euthyroid: Normal thyroid function. |
| hemi- | half | hemiplegia: Paralysis of one side of the body. |
| inter- | between | intercostal: Situated between the ribs. |
| intra- | within, inside | intravenous: Within a vein. |
| peri- | around, surrounding | pericardium: Fibroserous sac surrounding the heart. |
| poly- | many, much | polyuria: Excessive production of urine. |
| oligo- | few, scanty | oliguria: Reduced urine output. |
| pan- | all, entire | pancytopenia: Reduction of all three blood cell lines. |
| para- | beside, near, abnormal | paravertebral: Beside the vertebral column. |
| pre- | before (time or position) | prenatal: Before birth. |
| post- | after, behind | postoperative: Occurring after a surgical operation. |
| sub- | under, below, less than | subcutaneous: Beneath the skin. |
| supra- | above, over | suprapubic: Above the pubis. |
| trans- | across, through | transdermal: Through the skin. |
| ante- | before, in front of | antenatal: Before birth, during pregnancy. |
| contra- | against, opposite | contralateral: On the opposite side. |
| epi- | upon, above | epidermis: Outer layer of the skin. |
| endo- | within, inner | endocardium: Inner lining of the heart chambers. |
| exo- | outside, outward | exogenous: Originating outside the body. |
| extra- | outside, beyond | extracellular: Outside the cells. |
| hetero- | different, other | heterogeneous: Composed of unlike parts. |
| homo- | same, alike | homogeneous: Composed of uniform parts. |
| iso- | equal, same | isotonic: Having the same osmotic pressure as another solution. |
| macro- | large, long | macrocytosis: Presence of abnormally large red blood cells. |
| micro- | small | microcephaly: Abnormally small head. |
| mega- | large, enlarged | megacolon: Abnormal dilatation of the colon. |
| neo- | new | neonate: Infant in the first 28 days of life. |
| pseudo- | false, resembling | pseudocyst: Cyst-like collection lacking an epithelial lining. |
| retro- | behind, backward | retroperitoneal: Behind the peritoneum. |
| semi- | half, partial | semilunar: Half-moon shaped, as the semilunar valves. |
| syn-/sym- | together, joined (sym- before b, m, p) | syndrome: Set of signs and symptoms occurring together. |
| tri- | three | tricuspid: Having three cusps, as the right atrioventricular valve. |
| bi- | two, twice | bilateral: Affecting both sides. |
| uni- | one, single | unilateral: Affecting one side only. |
| quadri- | four | quadriplegia: Paralysis affecting all four limbs. |
| multi- | many, multiple | multiparous: Having borne several children. |
| meta- | change, beyond, after | metastasis: Spread of disease, typically cancer, to a distant site. |
| dia- | through, across, complete | diarrhoea: Frequent passage of loose stools. |
| ecto- | outside, outer | ectopic: Located away from the normal position. |
| mal- | bad, poor, abnormal | malnutrition: Deficiency, excess or imbalance of nutrient intake. |
| infra- | below, beneath | infraorbital: Below the orbit. |
| ab- | away from | abduction: Movement away from the midline. |
| ad- | toward, near | adduction: Movement toward the midline. |
| ana- | up, again, back | anabolism: Metabolic building of complex molecules. |
| nulli- | none, zero | nulliparous: Never having given birth. |
Suffixes
| Word part | Meaning | Example |
|---|---|---|
| -itis | inflammation | appendicitis: Inflammation of the vermiform appendix. |
| -osis | abnormal condition, process | thrombosis: Formation of a blood clot within a vessel. |
| -oma | tumour, mass | lipoma: Benign tumour of adipose tissue. |
| -pathy | disease, disorder | neuropathy: Disease or dysfunction of peripheral nerves. |
| -algia | pain | neuralgia: Pain along the distribution of a nerve. |
| -ectomy | surgical removal | appendectomy: Surgical removal of the appendix. |
| -otomy | cutting into, incision | laparotomy: Surgical incision into the abdominal cavity. |
| -ostomy | creation of an artificial opening | colostomy: Surgical opening of the colon onto the abdominal wall. |
| -plasty | surgical repair or reconstruction | angioplasty: Procedure to widen a narrowed blood vessel. |
| -scopy | visual examination | colonoscopy: Endoscopic examination of the colon. |
| -gram | record, image | electrocardiogram: Recording of the heart’s electrical activity. |
| -graphy | process of recording or imaging | angiography: Imaging of blood vessels with contrast. |
| -graph | instrument for recording | electroencephalograph: Device that records brain electrical activity. |
| -meter | instrument for measuring | sphygmomanometer: Instrument for measuring arterial blood pressure. |
| -metry | process of measuring | spirometry: Measurement of lung volumes and airflow. |
| -emia | condition of the blood | septicaemia: Presence of pathogens and their toxins in the bloodstream. |
| -uria | condition of the urine | haematuria: Presence of blood in the urine. |
| -penia | deficiency, decrease | leukopenia: Reduced white blood cell count. |
| -philia | attraction to, tendency toward, increase | eosinophilia: Increased eosinophil count in the blood. |
| -rrhea | flow, discharge | diarrhoea: Frequent passage of loose stools. |
| -rrhagia | bursting forth, haemorrhage | menorrhagia: Excessive or prolonged menstrual bleeding. |
| -rrhaphy | suture, surgical repair by stitching | herniorrhaphy: Surgical repair of a hernia by suturing. |
| -plegia | paralysis | paraplegia: Paralysis of the lower limbs. |
| -paresis | partial paralysis, weakness | hemiparesis: Weakness of one side of the body. |
| -spasm | involuntary contraction | bronchospasm: Sudden constriction of the bronchial muscles. |
| -megaly | enlargement | cardiomegaly: Enlargement of the heart. |
| -malacia | softening | osteomalacia: Softening of bone from defective mineralisation. |
| -sclerosis | hardening | atherosclerosis: Arterial disease with lipid-rich plaques in the vessel wall. |
| -stasis | stopping, control, standing still | haemostasis: Arrest of bleeding. |
| -lysis | breakdown, dissolution, loosening | haemolysis: Destruction of red blood cells. |
| -genesis | origin, formation | pathogenesis: Mechanism by which a disease develops. |
| -genic | producing, originating from | carcinogenic: Capable of causing cancer. |
| -trophy | nourishment, growth | hypertrophy: Increase in tissue size through enlargement of its cells. |
| -plasia | formation, development, cell growth | hyperplasia: Increase in tissue size through increased cell number. |
| -ptosis | drooping, downward displacement | blepharoptosis: Drooping of the upper eyelid. |
| -pexy | surgical fixation | orchiopexy: Surgical fixation of an undescended or mobile testis in the scrotum. |
| -cele | hernia, protrusion, swelling | hydrocele: Collection of fluid around the testis. |
| -centesis | puncture to remove fluid | paracentesis: Puncture of the peritoneal cavity to drain fluid. |
| -desis | binding, fusion | arthrodesis: Surgical fusion of a joint. |
| -dynia | pain | pleurodynia: Pain in the chest wall on breathing. |
| -iasis | condition, presence of | lithiasis: Formation of stones in a hollow organ or duct. |
| -ism | condition, state, disease process | hypothyroidism: Underactivity of the thyroid gland. |
| -ist | specialist, practitioner | cardiologist: Physician specialising in heart disease. |
| -logy | study of | cardiology: Branch of medicine concerned with the heart. |
| -oid | resembling, like | lipoid: Resembling fat. |
| -ous | pertaining to, having the nature of | cutaneous: Pertaining to the skin. |
| -tripsy | crushing | lithotripsy: Fragmentation of a stone, for example by shock waves. |
| -cyte | cell | erythrocyte: Red blood cell. |
| -blast | immature precursor cell, germ | osteoblast: Cell that forms new bone matrix. |
| -phagia | eating, swallowing | dysphagia: Difficulty swallowing. |
| -phobia | fear, aversion | claustrophobia: Fear of enclosed spaces. |
| -pnea | breathing | dyspnoea: Subjective sensation of difficult breathing. |
| -phasia | speech | aphasia: Loss or impairment of language ability. |
| -esthesia | sensation, feeling | anaesthesia: Loss of sensation, induced or pathological. |
| -rrhexis | rupture | myorrhexis: Rupture of a muscle. |
| -ia | condition, state (abstract noun) | pneumonia: Infection and inflammation of the lung parenchyma. |
| -ic | pertaining to | cardiac: Pertaining to the heart. |
| -lith | stone, calculus | cholelith: Gallstone. |
Combining roots
| Word part | Meaning | Example |
|---|---|---|
| cardi/o | heart | cardiomyopathy: disease of the heart muscle |
| angi/o | vessel | angiography: imaging of vessels after contrast injection |
| arteri/o | artery | arteritis: inflammation of an artery wall |
| ven/o | vein | venipuncture: puncture of a vein to sample blood or give fluid |
| phleb/o | vein | phlebitis: inflammation of a vein |
| vas/o | vessel; vas deferens | vasodilation: widening of blood vessels |
| vascul/o | small vessel; vascular | vasculitis: inflammation of blood vessel walls |
| aort/o | aorta | aortitis: inflammation of the aorta |
| atri/o | atrium (of the heart) | atrial fibrillation: rapid irregular atrial activity with an irregular ventricular response |
| ventricul/o | ventricle (heart or brain) | ventriculography: imaging of a ventricle, usually of the heart |
| valv/o | valve | valvotomy: incision of a stenosed valve |
| coron/o | crown; coronary artery | coronary angioplasty: catheter-based widening of a narrowed coronary artery |
| ather/o | porridge; fatty plaque | atherosclerosis: arterial disease with lipid plaques and hardening of the wall |
| sphygm/o | pulse | sphygmomanometer: device used to measure arterial blood pressure |
| embol/o | plug; embolus | pulmonary embolism: obstruction of a pulmonary artery by material carried in the blood |
| pneum/o | air; lung; breathing | pneumothorax: air in the pleural space |
| pneumon/o | lung | pneumonia: infection of the lung parenchyma |
| pulmon/o | lung | pulmonologist: physician specialised in lung diseases |
| bronch/o | bronchus | bronchoscopy: direct visual examination of the bronchi |
| bronchi/o | bronchus | bronchiectasis: permanent abnormal widening of the bronchi |
| bronchiol/o | bronchiole | bronchiolitis: inflammation of the bronchioles, typical in infants |
| trache/o | trachea | tracheostomy: surgical opening of the trachea through the neck |
| laryng/o | larynx | laryngitis: inflammation of the larynx |
| pharyng/o | pharynx | pharyngitis: inflammation of the pharynx |
| rhin/o | nose | rhinoplasty: surgical reshaping or repair of the nose |
| nas/o | nose | nasogastric tube: tube passed through the nose into the stomach |
| sinus/o | sinus; cavity | sinusitis: inflammation of the paranasal sinuses |
| thorac/o | chest; thorax | thoracotomy: surgical incision into the chest wall |
| pleur/o | pleura | pleurisy: inflammation of the pleura, often painful on breathing |
| alveol/o | alveolus; air sac | alveolitis: inflammation of the pulmonary alveoli |
| spir/o | breathing | spirometry: measurement of lung volumes and airflow |
| ox/o | oxygen | hypoxaemia: low oxygen level in arterial blood |
| capn/o | carbon dioxide; smoke | hypercapnia: raised carbon dioxide level in the blood |
| phon/o | voice; sound | dysphonia: abnormal voice quality, such as hoarseness |
| epiglott/o | epiglottis | epiglottitis: inflammation of the epiglottis, a potential airway emergency |
| atel/o | incomplete; imperfect | atelectasis: collapse or incomplete expansion of lung tissue |
| gastr/o | stomach | gastritis: inflammation of the stomach lining |
| enter/o | intestine (usually small intestine) | enteritis: inflammation of the intestine |
| col/o | colon | colectomy: surgical removal of part or all of the colon |
| duoden/o | duodenum | duodenal ulcer: ulcer in the first part of the small intestine |
| jejun/o | jejunum | jejunostomy: surgical opening into the jejunum, e.g. for feeding |
| ile/o | ileum | ileitis: inflammation of the ileum |
| cec/o | cecum | cecostomy: surgical opening of the cecum onto the abdominal wall |
| append/o | appendix | appendectomy: surgical removal of the vermiform appendix |
| sigmoid/o | sigmoid colon | sigmoidoscopy: endoscopic examination of the rectum and sigmoid colon |
| rect/o | rectum | rectocele: herniation of the rectum into the posterior vaginal wall |
| an/o | anus | perianal abscess: collection of pus around the anus |
| proct/o | anus and rectum | proctitis: inflammation of the rectum and anal canal |
| hepat/o | liver | hepatitis: inflammation of the liver |
| cholecyst/o | gallbladder | cholecystectomy: surgical removal of the gallbladder |
| chol/e | bile | cholestasis: impaired bile flow from the liver |
| choledoch/o | common bile duct | choledocholithiasis: presence of stones in the common bile duct |
| pancreat/o | pancreas | pancreatitis: inflammation of the pancreas |
| splen/o | spleen | splenomegaly: enlargement of the spleen |
| esophag/o | esophagus | esophagitis: inflammation of the esophagus |
| stomat/o | mouth | stomatitis: inflammation of the oral mucosa |
| or/o | mouth | oral route: administration or intake by mouth |
| gloss/o | tongue | glossitis: inflammation of the tongue |
| lingu/o | tongue | sublingual: situated or given under the tongue |
| dent/o | tooth | dentition: the number and arrangement of teeth, or the eruption of teeth |
| odont/o | tooth | periodontitis: inflammation of the tissues supporting the teeth |
| gingiv/o | gum | gingivitis: inflammation of the gums |
| sial/o | saliva; salivary gland | sialolithiasis: stones in a salivary gland or duct |
| cheil/o | lip | cheilitis: inflammation of the lips |
| bucc/o | cheek | buccal mucosa: lining of the inside of the cheek |
| pylor/o | pylorus | pyloric stenosis: narrowing of the gastric outlet |
| diverticul/o | diverticulum | diverticulitis: inflammation of colonic diverticula |
| abdomin/o | abdomen | abdominoplasty: surgical reshaping of the abdominal wall |
| lapar/o | abdominal wall; flank | laparoscopy: endoscopic examination of the abdominal cavity through small incisions |
| periton/o | peritoneum | peritonitis: inflammation of the peritoneum |
| nephr/o | kidney | nephritis: inflammation of the kidney |
| ren/o | kidney | renal failure: loss of the excretory and regulatory function of the kidneys |
| ur/o | urine; urinary tract | urology: specialty dealing with the urinary tract and male genital organs |
| ureter/o | ureter | ureteroscopy: endoscopic examination of the ureter |
| urethr/o | urethra | urethritis: inflammation of the urethra |
| cyst/o | bladder; sac | cystitis: inflammation of the urinary bladder |
| vesic/o | bladder; vesicle | vesicoureteral reflux: backward flow of urine from the bladder into the ureter |
| pyel/o | renal pelvis | pyelonephritis: infection of the renal pelvis and kidney |
| glomerul/o | glomerulus | glomerulonephritis: inflammation of the renal glomeruli |
| lith/o | stone; calculus | nephrolithiasis: stones in the kidney |
| meat/o | opening; meatus | meatal stenosis: narrowing of the external urethral opening |
| hyster/o | uterus | hysterectomy: surgical removal of the uterus |
| metr/o | uterus; measure | endometriosis: endometrial tissue located outside the uterine cavity |
| uter/o | uterus | uterine prolapse: descent of the uterus into or through the vagina |
| salping/o | uterine tube; auditory tube | salpingitis: inflammation of the uterine tube |
| oophor/o | ovary | oophorectomy: surgical removal of an ovary |
| ovari/o | ovary | ovarian cyst: fluid-filled sac within or on an ovary |
| colp/o | vagina | colposcopy: magnified examination of the cervix and vagina |
| vagin/o | vagina | vaginitis: inflammation of the vagina |
| cervic/o | neck; cervix of the uterus | cervicitis: inflammation of the uterine cervix |
| mamm/o | breast | mammography: radiographic imaging of the breast |
| mast/o | breast | mastectomy: surgical removal of breast tissue |
| gynec/o | woman; female reproductive system | gynaecology: specialty concerned with the female reproductive system |
| orchi/o | testis | orchitis: inflammation of the testis |
| orchid/o | testis | orchidopexy: surgical fixation of an undescended testis in the scrotum |
| epididym/o | epididymis | epididymitis: inflammation of the epididymis |
| prostat/o | prostate | prostatitis: inflammation of the prostate gland |
| balan/o | glans penis | balanitis: inflammation of the glans penis |
| vulv/o | vulva | vulvovaginitis: inflammation of the vulva and vagina |
| gonad/o | gonad (ovary or testis) | hypogonadism: reduced gonadal hormone production or function |
| spermat/o | sperm; spermatozoon | spermatogenesis: the process of sperm cell production in the testis |
| embryo/o | embryo | embryology: study of prenatal development |
| fet/o | fetus | fetoscopy: endoscopic visualisation of the fetus in the uterus |
| nat/i | birth | neonatal: relating to the first four weeks after birth |
| par/o | to bear; childbirth | multiparous: having given birth two or more times |
| men/o | menstruation; month | amenorrhoea: absence of menstrual periods |
| lact/o | milk | lactation: production and secretion of breast milk |
| galact/o | milk | galactorrhoea: milk discharge from the breast unrelated to nursing |
| amni/o | amnion; amniotic sac | amniocentesis: sampling of amniotic fluid through the abdominal wall |
| chori/o | chorion | chorioamnionitis: infection of the fetal membranes and amniotic fluid |
| gravid/o | pregnant | gravidity: the number of times a woman has been pregnant |
| toc/o | labour; childbirth | dystocia: abnormally slow or difficult labour |
| ov/o | egg; ovum | ovulation: release of an oocyte from the ovary |
| episi/o | vulva | episiotomy: surgical incision of the perineum during childbirth |
| perine/o | perineum | perineorrhaphy: surgical repair of the perineum |
| hymen/o | hymen | imperforate hymen: congenital hymen that completely blocks the vaginal opening |
| thel/o | nipple | thelarche: onset of breast development at puberty |
| neur/o | nerve | neuropathy: disease or damage of nerves |
| encephal/o | brain (encephalon) | encephalitis: inflammation of the brain |
| cerebr/o | cerebrum, cerebral hemispheres | cerebral: relating to the cerebrum |
| mening/o | meninges | meningitis: inflammation of the meninges |
| myel/o | spinal cord (also bone marrow, by context) | myelopathy: disease of the spinal cord |
| psych/o | mind, psyche | psychosis: severe mental disorder with loss of contact with reality |
| cephal/o | head | hydrocephalus: accumulation of cerebrospinal fluid within the cranium |
| crani/o | skull (cranium) | craniotomy: surgical opening of the skull |
| gli/o | glue; glial (supporting) cells of the nervous system | glioma: tumour arising from glial cells |
| radicul/o | nerve root | radiculopathy: disorder of a spinal nerve root |
| gangli/o | ganglion | ganglionectomy: surgical removal of a ganglion |
| esthesi/o | sensation, feeling | anaesthesia: loss of sensation |
| somn/o | sleep | insomnia: persistent difficulty falling or staying asleep |
| narc/o | stupor, numbness, sleep | narcolepsy: chronic disorder with irresistible attacks of sleep |
| mnem/o | memory | amnesia: loss of memory |
| phren/o | mind (also diaphragm, by context) | schizophrenia: chronic psychotic disorder with disturbed thought and perception |
| ment/o | mind, mental function | dementia: acquired progressive decline of cognitive function |
| oste/o | bone | osteoporosis: reduced bone mass with increased fracture risk |
| arthr/o | joint | arthritis: inflammation of a joint |
| chondr/o | cartilage | chondroma: benign tumour of cartilage |
| my/o | muscle | myalgia: muscle pain |
| ten/o | tendon | tenotomy: surgical cutting of a tendon |
| tendin/o | tendon | tendinitis: inflammation of a tendon |
| fasci/o | fascia; band | fasciitis: inflammation of a fascia |
| burs/o | bursa (synovial sac) | bursitis: inflammation of a bursa |
| ligament/o | ligament | ligamentous: relating to a ligament |
| vertebr/o | vertebra | intervertebral: between two vertebrae |
| spondyl/o | vertebra, spine | spondylosis: degenerative change of the vertebrae |
| cost/o | rib | costochondritis: inflammation of the costal cartilages |
| stern/o | sternum | sternotomy: surgical incision through the sternum |
| scapul/o | scapula (shoulder blade) | scapulohumeral: relating to the scapula and humerus |
| humer/o | humerus (upper arm bone) | humeral: relating to the humerus |
| radi/o | radius (forearm bone); also radiation, by context | radioulnar: relating to the radius and ulna |
| uln/o | ulna | ulnar: relating to the ulna |
| carp/o | carpus (wrist bones) | carpal tunnel: passage at the wrist containing the median nerve and flexor tendons |
| metacarp/o | metacarpus (hand bones) | metacarpal: bone of the metacarpus |
| phalang/o | phalanx (bone of a finger or toe) | phalangeal: relating to a phalanx |
| pelv/i | pelvis | pelvimetry: measurement of the pelvic dimensions |
| ili/o | ilium (hip bone) | iliac: relating to the ilium |
| femor/o | femur (thigh bone) | femoral: relating to the femur or thigh |
| patell/o | patella (kneecap) | patellar: relating to the patella |
| tibi/o | tibia (shin bone) | tibial: relating to the tibia |
| fibul/o | fibula | fibular: relating to the fibula |
| tars/o | tarsus (ankle bones); also eyelid plate, by context | tarsal: relating to the tarsus |
| calcane/o | calcaneus (heel bone) | calcaneal: relating to the heel bone |
| dactyl/o | finger or toe (digit) | polydactyly: presence of extra digits |
| kinesi/o | movement | dyskinesia: abnormal involuntary movement |
| cutane/o | skin | subcutaneous: beneath the skin |
| derm/o | skin | hypodermis: deepest layer of the skin |
| dermat/o | skin | dermatitis: inflammation of the skin |
| kerat/o | horny tissue (keratin); also cornea, by context | keratosis: thickening of the horny layer of the skin |
| melan/o | black; melanin pigment | melanoma: malignant tumour of melanocytes |
| onych/o | nail | onychomycosis: fungal infection of the nail |
| trich/o | hair | trichology: study of hair and its disorders |
| hidr/o | sweat | hyperhidrosis: excessive sweating |
| seb/o | sebum; sebaceous gland | seborrhoea: excessive sebaceous secretion |
| xer/o | dry | xeroderma: abnormal dryness of the skin |
| lip/o | fat, lipid | lipoma: benign tumour of fat tissue |
| adip/o | fat (adipose tissue) | adipocyte: fat-storing cell |
| hem/o | blood | haemorrhage: escape of blood from vessels |
| hemat/o | blood | haematology: study of blood and blood-forming tissues |
| erythr/o | red | erythrocyte: red blood cell |
| leuk/o | white | leukaemia: malignant proliferation of white blood cell precursors |
| thromb/o | clot | thrombosis: formation of a clot within a blood vessel |
| cyt/o | cell | cytology: study of cells |
| lymph/o | lymph; lymphatic tissue | lymphoma: malignant tumour of lymphoid tissue |
| lymphaden/o | lymph node | lymphadenopathy: enlargement or disease of lymph nodes |
| immun/o | immunity, protection | immunodeficiency: reduced ability of the immune system to fight infection |
| granul/o | granule, small grain | granulocyte: white cell with cytoplasmic granules |
| mon/o | single, one | monocyte: white cell with a single, indented nucleus |
| fibr/o | fibre, fibrous tissue | fibrosis: excess formation of fibrous connective tissue |
| coagul/o | clotting, coagulation | coagulopathy: disorder of blood clotting |
| sider/o | iron | sideropenia: iron deficiency |
| bacteri/o | bacteria | bacteriology: study of bacteria |
| vir/o | virus | virology: study of viruses |
| myc/o | fungus | mycosis: fungal infection |
| parasit/o | parasite | parasitology: study of parasites and the diseases they cause |
| endocrin/o | endocrine system, hormone-secreting glands | endocrinology: study of hormones and endocrine glands |
| thyr/o | thyroid gland | thyrotoxicosis: clinical state due to excess thyroid hormone |
| thyroid/o | thyroid gland | thyroidectomy: surgical removal of the thyroid gland |
| adren/o | adrenal gland | adrenalectomy: surgical removal of an adrenal gland |
| pituitar/o | pituitary gland (hypophysis) | hypopituitarism: reduced secretion of pituitary hormones |
| gluc/o | glucose, sweet | gluconeogenesis: synthesis of glucose from non-carbohydrate precursors |
| glyc/o | sugar, glucose | hyperglycaemia: abnormally high blood glucose |
| ophthalm/o | eye | ophthalmology: medical specialty of the eye and its disorders |
| ocul/o | eye | intraocular: within the eye |
| opt/o | vision, eye | optometry: measurement of vision and refractive error |
| retin/o | retina | retinopathy: disease of the retina |
| ot/o | ear | otitis: inflammation of the ear |
| audi/o | hearing | audiometry: measurement of hearing |
| myring/o | tympanic membrane (eardrum) | myringotomy: incision of the eardrum |
| tympan/o | eardrum; middle ear (tympanic cavity) | tympanometry: test of middle ear pressure and eardrum mobility |
| cochle/o | cochlea | cochlear implant: device that electrically stimulates the cochlear nerve |
| irid/o | iris | iridectomy: surgical removal of part of the iris |
| corne/o | cornea | corneal: relating to the cornea |
| blephar/o | eyelid | blepharitis: inflammation of the eyelid margins |
| path/o | disease, suffering | pathology: study of the causes and effects of disease |
| onc/o | tumour, mass | oncology: study and treatment of tumours, especially cancer |
| carcin/o | cancer, carcinoma (epithelial malignancy) | carcinogenesis: process by which cancer develops |
| sarc/o | flesh, connective tissue | sarcoma: malignant tumour of connective tissue |
| tox/o | poison | toxicology: study of poisons and their effects |
| cry/o | cold | cryotherapy: treatment using extreme cold |
| therm/o | heat, temperature | hyperthermia: abnormally high body temperature |
| somat/o | body | psychosomatic: relating to mind and body together |
| viscer/o | internal organs (viscera) | visceral: relating to the internal organs |
| dors/o | back, posterior | dorsal: relating to the back or posterior surface |
| ventr/o | belly, anterior | ventral: relating to the front or belly side |
| later/o | side | bilateral: affecting both sides |
| medi/o | middle | mediolateral: from the midline to the side |
| caud/o | tail, toward the lower end of the body | caudal: toward the tail or lower end |
| proxim/o | nearest to the trunk or point of origin | proximal: nearer to the trunk or point of attachment |
| dist/o | far from the trunk or point of origin | distal: farther from the trunk or point of attachment |
| anter/o | front, before | anterolateral: in front and to the side |
| poster/o | back, behind | posteroanterior: directed from back to front, as in a chest radiograph projection |
Medical abbreviations
481 entries
A
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| AAA | abdominal aortic aneurysm | |
| ABC | Airway, breathing, circulation | AmbiguousAlso airway, breathing, circulation approach versus ATP-binding cassette (transporters) in biochemistry; in emergency care it is the primary survey. |
| ABG | Arterial blood gas | |
| ABPI | ankle-brachial pressure index | |
| AC | before meals (ante cibum) | |
| ACA | anterior cerebral artery | |
| ACEI | angiotensin-converting enzyme inhibitor | |
| ACLS | Advanced cardiac life support | |
| ACS | acute coronary syndrome | |
| ACTH | Adrenocorticotropic hormone | |
| AD | right ear (auris dextra) | AmbiguousError-prone (ISMP): AD, AS and AU are mistaken for OD, OS and OU (eye) and for each other. Write "right ear". |
| ADH | Antidiuretic hormone (vasopressin) | |
| ADL | Activities of daily living | |
| ADPKD | autosomal dominant polycystic kidney disease | |
| ADR | adverse drug reaction | |
| AED | antiepileptic drug | AmbiguousAntiepileptic drug in neurology; automated external defibrillator in resuscitation. Context decides. |
| AF | atrial fibrillation | |
| AFB | Acid-fast bacilli | |
| AFL | atrial flutter | |
| AIDS | Acquired immunodeficiency syndrome | |
| AKI | acute kidney injury | |
| ALL | Acute lymphoblastic leukaemia | |
| ALP | Alkaline phosphatase | |
| ALS | amyotrophic lateral sclerosis or advanced life support | AmbiguousAmbiguous: amyotrophic lateral sclerosis (neurology) versus advanced life support (resuscitation). Context decides. |
| ALT | Alanine aminotransferase | |
| AML | Acute myeloid leukaemia | |
| ANA | Antinuclear antibodies | |
| ANC | Antenatal care; absolute neutrophil count | AmbiguousAntenatal care in obstetrics; absolute neutrophil count in haematology. |
| ANCA | Antineutrophil cytoplasmic antibodies | |
| aPTT | Activated partial thromboplastin time | |
| ARB | angiotensin receptor blocker | |
| ARDS | acute respiratory distress syndrome | |
| ART | Antiretroviral therapy; assisted reproductive technology | AmbiguousAntiretroviral therapy in HIV medicine; assisted reproductive technology in fertility care. |
| AS | left ear (auris sinistra) | AmbiguousError-prone (ISMP): mistaken for OS (left eye); AS also means aortic stenosis or ankylosing spondylitis in other contexts. Write "left ear". |
| AS | Aortic stenosis; ankylosing spondylitis; left ear (AS, error-prone in prescribing) | AmbiguousAortic stenosis in cardiology, ankylosing spondylitis in rheumatology; also left ear in prescribing. |
| ASA | American Society of Anesthesiologists (physical status class) | AmbiguousAlso used for acetylsalicylic acid (aspirin) in some countries; in anaesthesia it is the physical status classification. |
| ASD | atrial septal defect | |
| AST | Aspartate aminotransferase | |
| ATLS | Advanced trauma life support | |
| ATN | acute tubular necrosis | |
| AU | both ears (auris uterque) | AmbiguousError-prone (ISMP): mistaken for OU (both eyes). Write "both ears". |
| AVB | atrioventricular block | |
| AVF | arteriovenous fistula (dialysis access) | |
| AVM | arteriovenous malformation | |
| AVPU | Alert, voice, pain, unresponsive (consciousness scale) | |
| AXR | Abdominal X-ray | |
| AZT | zidovudine (azidothymidine) | AmbiguousError-prone (ISMP): mistaken for azathioprine or aztreonam. Write the generic name. |
B
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| BAL | bronchoalveolar lavage | |
| BCG | Bacillus Calmette-Guérin (vaccine) | |
| BID | twice daily (bis in die) | |
| BiPAP | bilevel positive airway pressure | |
| BLS | Basic life support | |
| BMI | Body mass index | |
| BMP | Basic metabolic panel | |
| BNP | B-type natriuretic peptide | |
| BP | blood pressure | |
| BPH | benign prostatic hyperplasia | |
| BS | Blood sugar; bowel sounds; breath sounds | AmbiguousThree common meanings in clinical notes; avoid in favour of the full term. |
| BSA | Body surface area | |
| BT | bedtime | AmbiguousError-prone (ISMP): mistaken for BID (twice daily) when poorly written. Write "bedtime". |
| BUN | blood urea nitrogen | |
| BV | Bacterial vaginosis |
C
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| CA | Cancer; carbohydrate antigen; cardiac arrest | AmbiguousCancer, carbohydrate antigen (e.g. CA-125) and cardiac arrest are all used; read from context. |
| CABG | coronary artery bypass grafting | |
| CAD | coronary artery disease | |
| CAH | Congenital adrenal hyperplasia | |
| CAP | Community-acquired pneumonia | AmbiguousAlso appears as a general word (cap) and in some contexts for capsule; here read as pneumonia. |
| CAPD | continuous ambulatory peritoneal dialysis | |
| CAUTI | catheter-associated urinary tract infection | |
| CBC | Complete blood count | |
| cc | cubic centimetre | AmbiguousError-prone (ISMP): mistaken for U (units) when handwritten. Use mL instead. |
| CC | Chief complaint | AmbiguousAlso creatinine clearance and cubic centimetre; in history-taking it means chief complaint. |
| CCU | Coronary care unit | |
| CD | Cluster of differentiation; Crohn disease | AmbiguousCluster of differentiation (immunology, e.g. CD4) or Crohn disease (gastroenterology); context decides. |
| CDI | Clostridioides difficile infection | |
| CF | cystic fibrosis | |
| CIN | Cervical intraepithelial neoplasia | |
| CJD | Creutzfeldt-Jakob disease | |
| CK | Creatine kinase | |
| CKD | chronic kidney disease | |
| CLL | Chronic lymphocytic leukaemia | |
| CML | Chronic myeloid leukaemia | |
| CMV | Cytomegalovirus | |
| CNS | central nervous system | |
| CO | cardiac output | AmbiguousCardiac output in physiology; also carbon monoxide (CO) in toxicology and pulmonary function (DLCO). Context decides. |
| COPD | chronic obstructive pulmonary disease | |
| CP | Cerebral palsy; chest pain | AmbiguousCerebral palsy in paediatrics; chest pain in adult medicine. |
| CPAP | continuous positive airway pressure | |
| CPR | Cardiopulmonary resuscitation | |
| CPZ | chlorpromazine | AmbiguousError-prone (ISMP): mistaken for compazine (prochlorperazine). Write the generic name in full. |
| CRE | Carbapenem-resistant Enterobacterales | |
| CRH | Corticotropin-releasing hormone | |
| CRP | C-reactive protein | |
| CRRT | continuous renal replacement therapy | |
| CRT | cardiac resynchronisation therapy | AmbiguousCardiac resynchronisation therapy in cardiology; capillary refill time in emergency assessment. Context decides. |
| CS | Caesarean section | |
| CSF | cerebrospinal fluid | |
| CT | Computed tomography | AmbiguousAlso connective tissue and clotting time in some contexts; in imaging it means computed tomography. |
| CTA | CT angiography | |
| CTG | Cardiotocography | |
| CTPA | CT pulmonary angiography | |
| CVA | cerebrovascular accident (stroke) | |
| CVP | Central venous pressure | |
| CVVH | continuous venovenous haemofiltration | |
| CXR | Chest X-ray |
D
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| D/C | discharge or discontinue | AmbiguousAmbiguous (ISMP): discharge versus discontinue; medications have been stopped or continued in error. Write the word in full. |
| DAPT | dual antiplatelet therapy | |
| DAT | Direct antiglobulin test (Coombs test) | |
| DBS | deep brain stimulation | |
| DDx | Differential diagnosis | |
| DEXA | Dual-energy X-ray absorptiometry | |
| DI | Diabetes insipidus; diagnostic imaging | AmbiguousDiabetes insipidus in endocrinology; diagnostic imaging in radiology. |
| DIC | Disseminated intravascular coagulation | |
| DKA | Diabetic ketoacidosis | |
| DLCO | diffusing capacity of the lung for carbon monoxide | |
| DM | Diabetes mellitus | AmbiguousAlso used for dermatomyositis and myotonic dystrophy; context decides. |
| DNR | Do not resuscitate | |
| DOAC | direct oral anticoagulant | |
| DOB | Date of birth | |
| DSA | Digital subtraction angiography | |
| DVT | deep vein thrombosis | |
| DWI | Diffusion-weighted imaging | |
| Dx | diagnosis |
E
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| EBL | Estimated blood loss | |
| EBV | Epstein-Barr virus | |
| ECG | electrocardiogram | |
| ECMO | Extracorporeal membrane oxygenation | |
| ED | Emergency department; erectile dysfunction | AmbiguousEmergency department in hospital notes; erectile dysfunction in urology and sexual medicine. |
| EDD | Estimated date of delivery | |
| EDH | extradural (epidural) haematoma | |
| EEG | electroencephalogram | |
| EF | ejection fraction | |
| eGFR | estimated glomerular filtration rate | |
| EKG | electrocardiogram (German Elektrokardiogramm) | |
| ELISA | Enzyme-linked immunosorbent assay | |
| EMG | electromyography | |
| EMS | Emergency medical services | |
| ENT | Ear, nose and throat (otorhinolaryngology) | |
| EP | Ectopic pregnancy | |
| ER | Emergency room; oestrogen receptor; endoplasmic reticulum | AmbiguousEmergency room in clinical settings, oestrogen receptor in oncology, endoplasmic reticulum in cell biology. |
| ERAS | Enhanced recovery after surgery | |
| ERCP | Endoscopic retrograde cholangiopancreatography | |
| ESBL | Extended-spectrum beta-lactamase | |
| ESR | Erythrocyte sedimentation rate | |
| ESRD | end-stage renal disease | |
| ESWL | extracorporeal shock wave lithotripsy | |
| ETCO2 | End-tidal carbon dioxide | |
| ETT | endotracheal tube | AmbiguousEndotracheal tube in airway care and anaesthesia; also exercise tolerance test in cardiology. Context decides. |
| EUA | Examination under anaesthesia | |
| EVD | external ventricular drain |
F
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| F/U | Follow-up | |
| FAST | Focused assessment with sonography in trauma | AmbiguousAlso an acronym for the stroke symptom check (face, arm, speech, time); context decides. |
| FBG | Fasting blood glucose | |
| FEV1 | forced expiratory volume in one second | |
| FFP | Fresh frozen plasma | |
| FH | Family history | AmbiguousAlso fetal heart in obstetric notes and familial hypercholesterolaemia; in history-taking it means family history. |
| FHR | Fetal heart rate | |
| FiO2 | fraction of inspired oxygen | |
| FNA | Fine-needle aspiration | |
| FOBT | Faecal occult blood test | |
| FSH | Follicle-stimulating hormone | |
| FVC | forced vital capacity | |
| Fx | fracture |
G
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| G6PD | Glucose-6-phosphate dehydrogenase (deficiency) | |
| GA | Gestational age; general anaesthesia | AmbiguousGestational age in obstetrics; general anaesthesia in surgery. |
| GBS | Guillain-Barré syndrome | |
| GCS | Glasgow Coma Scale | |
| GDM | Gestational diabetes mellitus | |
| GERD | Gastro-oesophageal reflux disease | |
| GETA | General endotracheal anaesthesia | |
| GFR | glomerular filtration rate | |
| GGT | Gamma-glutamyl transferase | |
| GH | Growth hormone | |
| GI | Gastrointestinal | |
| GLP-1 | Glucagon-like peptide 1 | |
| GN | glomerulonephritis | |
| GnRH | Gonadotropin-releasing hormone | |
| GTN | glyceryl trinitrate (nitroglycerin) | |
| gtt | drops (guttae) |
H
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| H. pylori | Helicobacter pylori | |
| HAP | Hospital-acquired pneumonia | |
| HAV | Hepatitis A virus | |
| Hb | Haemoglobin | |
| HbA1c | Glycated haemoglobin | |
| HbS | Haemoglobin S (sickle haemoglobin) | |
| HBsAg | Hepatitis B surface antigen | |
| HBV | Hepatitis B virus | |
| HCC | Hepatocellular carcinoma | |
| hCG | Human chorionic gonadotropin | |
| HCT | hydrocortisone, hydrochlorothiazide or haematocrit | AmbiguousAmbiguous (ISMP): HCT has been mistaken for hydrocortisone, hydrochlorothiazide or haematocrit. Use full names. |
| Hct | Haematocrit | |
| HCTZ | hydrochlorothiazide | AmbiguousError-prone (ISMP): mistaken for hydrocortisone (HCT). Write the generic name in full. |
| HCV | Hepatitis C virus | |
| HD | haemodialysis | AmbiguousHaemodialysis in nephrology; also Huntington disease and hospital day in other contexts. Spell out when unclear. |
| HDU | High-dependency unit | |
| HE | Hepatic encephalopathy | |
| HEENT | Head, eyes, ears, nose and throat | |
| HELLP | Haemolysis, elevated liver enzymes, low platelets (syndrome) | |
| HF | heart failure | |
| HFNC | high-flow nasal cannula (oxygen) | |
| HFpEF | heart failure with preserved ejection fraction | |
| HFrEF | heart failure with reduced ejection fraction | |
| HHS | Hyperosmolar hyperglycaemic state | |
| HIT | Heparin-induced thrombocytopenia | |
| HIV | Human immunodeficiency virus | |
| HL | Hodgkin lymphoma | |
| HPI | History of present illness | |
| HPV | Human papillomavirus | |
| HR | heart rate | |
| HRCT | High-resolution computed tomography | |
| HRT | Hormone replacement therapy | |
| HS | at bedtime (hora somni) or half-strength | AmbiguousError-prone (ISMP): can mean at bedtime or half-strength, and may be mistaken for each other. Write "at bedtime" or "half-strength" in full. |
| HSV | Herpes simplex virus | |
| HTN | hypertension | |
| HUS | Haemolytic uraemic syndrome | |
| Hx | history |
I
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| I&D | Incision and drainage | |
| IBD | Inflammatory bowel disease | |
| IBS | Irritable bowel syndrome | |
| ICD | implantable cardioverter-defibrillator | |
| ICH | intracerebral haemorrhage | |
| ICP | intracranial pressure | |
| ICU | Intensive care unit | |
| IDA | Iron-deficiency anaemia | |
| IE | infective endocarditis | |
| IFG | Impaired fasting glucose | |
| IGF-1 | Insulin-like growth factor 1 | |
| IGRA | Interferon-gamma release assay | |
| IGT | Impaired glucose tolerance | |
| IHD | ischaemic heart disease | |
| ILD | interstitial lung disease | |
| IM | intramuscular | |
| IN | intranasal | |
| INR | International normalised ratio | |
| IO | Intraosseous (access) | |
| IPF | idiopathic pulmonary fibrosis | |
| ITP | Immune thrombocytopenia (immune thrombocytopenic purpura) | |
| IU | international unit | Do Not UseJoint Commission Do Not Use: can be mistaken for IV (intravenous) or the number 10. Write out "International Unit". |
| IUD | Intrauterine device | |
| IUGR | Intrauterine growth restriction | |
| IV | intravenous | |
| IVF | In vitro fertilisation | |
| IVP | intravenous push | |
| IVPB | intravenous piggyback | |
| IVU | Intravenous urography |
J
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| JVP | jugular venous pressure |
K
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| KUB | kidneys, ureters and bladder (plain abdominal film) |
L
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| LA | Local anaesthesia; left atrium | AmbiguousLocal anaesthesia in surgery; left atrium in cardiology; also long-acting in prescribing. |
| LAD | left anterior descending artery or left axis deviation | AmbiguousAmbiguous: left anterior descending artery in coronary anatomy, left axis deviation on the ECG; also lymphadenopathy in some texts. |
| LBBB | left bundle branch block | |
| LC | Laparoscopic cholecystectomy | |
| LCx | left circumflex artery | |
| LDH | Lactate dehydrogenase | |
| LES | Lower oesophageal sphincter | AmbiguousAlso abbreviates systemic lupus erythematosus in some languages (Spanish and Italian: LES); context decides. |
| LFT | Liver function tests | |
| LGIB | Lower gastrointestinal bleeding | |
| LH | Luteinising hormone | |
| LLETZ | Large loop excision of the transformation zone | |
| LMA | Laryngeal mask airway | |
| LMN | lower motor neuron | |
| LMP | Last menstrual period | |
| LMWH | low-molecular-weight heparin | |
| LOC | Loss of consciousness; level of consciousness | AmbiguousLoss of consciousness versus level of consciousness; read from context. |
| LP | lumbar puncture | |
| LRTI | Lower respiratory tract infection | |
| LTOT | long-term oxygen therapy | |
| LV | left ventricle | |
| LVEF | left ventricular ejection fraction | |
| LVH | left ventricular hypertrophy |
M
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| MAOI | monoamine oxidase inhibitor | |
| MAP | Mean arterial pressure | AmbiguousAlso used for mean airway pressure and mitogen-activated protein (kinase); in critical care it is mean arterial pressure. |
| MCA | middle cerebral artery | |
| MCH | Mean corpuscular haemoglobin | |
| MCHC | Mean corpuscular haemoglobin concentration | |
| MCV | Mean corpuscular volume | |
| MDS | Myelodysplastic syndrome | |
| MDT | Multidisciplinary team | |
| MEN | Multiple endocrine neoplasia | |
| MG | myasthenia gravis | AmbiguousMyasthenia gravis in neurology; not to be confused with mg (milligram), which is lower case. |
| MgSO4 | magnesium sulfate | Do Not UseJoint Commission Do Not Use: can be confused with morphine sulfate. Write "magnesium sulfate". |
| MGUS | Monoclonal gammopathy of undetermined significance | |
| MI | myocardial infarction | AmbiguousUsually myocardial infarction; also used for mitral insufficiency (older term for mitral regurgitation). Spell out when unclear. |
| MM | Multiple myeloma | |
| MODS | Multiple organ dysfunction syndrome | |
| MR | Magnetic resonance; mitral regurgitation | AmbiguousMagnetic resonance in imaging; mitral regurgitation in cardiology; also modified release in prescribing. |
| MRA | Magnetic resonance angiography | |
| MRCP | Magnetic resonance cholangiopancreatography | |
| MRI | Magnetic resonance imaging | |
| mRS | modified Rankin Scale | |
| MRSA | Methicillin-resistant Staphylococcus aureus | |
| MS | morphine sulfate or magnesium sulfate (also multiple sclerosis, mitral stenosis) | Do Not UseJoint Commission Do Not Use for medication orders: can mean morphine sulfate or magnesium sulfate and be confused for one another. Write out the full drug name. Outside orders MS also commonly means multiple sclerosis or mitral stenosis, so spell it out whenever the context is not obvious. |
| MSO4 | morphine sulfate | Do Not UseJoint Commission Do Not Use: can be confused with magnesium sulfate. Write "morphine sulfate". |
| MSSA | Methicillin-sensitive Staphylococcus aureus | |
| MTX | methotrexate | AmbiguousError-prone (ISMP): mistaken for mitoxantrone. Write "methotrexate" in full. |
N
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| N/V | Nausea and vomiting | |
| NAD | No abnormality detected | AmbiguousAlso nicotinamide adenine dinucleotide in biochemistry; in clinical notes it means no abnormality detected. |
| NAFLD | Non-alcoholic fatty liver disease | |
| NASH | Non-alcoholic steatohepatitis | |
| NBM | Nil by mouth | |
| NCS | nerve conduction studies | |
| NEWS | National Early Warning Score | |
| NHL | Non-Hodgkin lymphoma | |
| NIHSS | National Institutes of Health Stroke Scale | |
| NIV | non-invasive ventilation | |
| NKDA | no known drug allergies | |
| NNT | number needed to treat | |
| NPH | normal pressure hydrocephalus | |
| NPO | nil by mouth (nil per os) | |
| NPV | negative predictive value | |
| NS | nephrotic syndrome | AmbiguousNephrotic syndrome in nephrology; also normal saline (a common prescribing abbreviation) and nervous system. Write normal saline in full in orders. |
| NSAID | non-steroidal anti-inflammatory drug | |
| NSTEMI | non-ST-elevation myocardial infarction | |
| NTM | Nontuberculous mycobacteria | |
| NYHA | New York Heart Association (functional class) |
O
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| OCP | Oral contraceptive pill | |
| OD | once daily, right eye (oculus dexter) or overdose | AmbiguousAmbiguous (ISMP): can mean once daily, right eye or overdose; an eye drop ordered "OD" has been given orally. Write "once daily" or "right eye". |
| OGD | Oesophagogastroduodenoscopy | |
| OGTT | Oral glucose tolerance test | |
| OPD | Outpatient department | |
| OR | Operating room (theatre) | AmbiguousAlso odds ratio in statistics; in clinical settings it means operating room. |
| ORIF | Open reduction and internal fixation | |
| OS | left eye (oculus sinister) or mouth (os) | AmbiguousAmbiguous (ISMP): left eye versus "by mouth" (os) and confusable with OD. Write "left eye". |
| OSA | obstructive sleep apnoea | |
| OTC | over the counter | |
| OU | both eyes (oculus uterque) |
P
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| PA | Posteroanterior (radiographic projection); pulmonary artery | AmbiguousPosteroanterior projection in radiology; pulmonary artery in cardiology; also physician assistant in some countries. |
| PAC | premature atrial contraction | |
| PaCO2 | arterial partial pressure of carbon dioxide | |
| PACU | Post-anaesthesia care unit | |
| PAD | peripheral arterial disease | |
| PAH | pulmonary arterial hypertension | |
| PaO2 | arterial partial pressure of oxygen | |
| PBC | Primary biliary cholangitis | |
| PC | after meals (post cibum) | |
| PCA | patient-controlled analgesia | AmbiguousAmbiguous (ISMP): can be read as procainamide; in neurology PCA is also the posterior cerebral artery. Spell out the drug or the context. |
| PCI | percutaneous coronary intervention | |
| PCOS | Polycystic ovary syndrome | |
| PCR | Polymerase chain reaction | |
| PD | peritoneal dialysis or Parkinson disease | AmbiguousAmbiguous: peritoneal dialysis (renal) versus Parkinson disease (neurology); also pharmacodynamics. Spell out when context is unclear. |
| PDA | patent ductus arteriosus or posterior descending artery | AmbiguousAmbiguous: patent ductus arteriosus (congenital) versus posterior descending artery (coronary anatomy). |
| PE | pulmonary embolism; also physical examination, pleural effusion | AmbiguousAmbiguous: pulmonary embolism, physical examination and pleural effusion are all in common use. Context decides. |
| PEA | Pulseless electrical activity | |
| PEEP | positive end-expiratory pressure | |
| PEFR | peak expiratory flow rate | |
| PEG | Percutaneous endoscopic gastrostomy | |
| PET | Positron emission tomography | |
| PFT | pulmonary function tests | |
| PID | Pelvic inflammatory disease; prolapsed intervertebral disc | AmbiguousPelvic inflammatory disease in gynaecology; prolapsed intervertebral disc in orthopaedics and neurology. |
| PIH | Pregnancy-induced hypertension | |
| PLT | Platelet count | |
| PMH | Past medical history | |
| PNH | Paroxysmal nocturnal haemoglobinuria | |
| PNS | peripheral nervous system | |
| PO | by mouth (per os) | |
| POD | Postoperative day | |
| PONV | Postoperative nausea and vomiting | |
| PPH | Postpartum haemorrhage | |
| PPI | proton pump inhibitor | |
| PPM | permanent pacemaker | |
| PPROM | Preterm premature rupture of membranes | |
| PPV | positive predictive value | |
| PR | per rectum | |
| PRBC | Packed red blood cells | |
| PrEP | Pre-exposure prophylaxis | |
| PRL | Prolactin | |
| PRN | as needed (pro re nata) | |
| PROM | Premature rupture of membranes | |
| PSC | Primary sclerosing cholangitis | |
| PT | Prothrombin time; also physical therapy, patient | AmbiguousProthrombin time in the laboratory (reported with INR); in clinical notes PT also stands for physical therapy (or physical therapist) and for patient. Spell out when unclear. |
| PTH | Parathyroid hormone | |
| PTX | pneumothorax | |
| PUD | Peptic ulcer disease | |
| PVC | premature ventricular contraction |
Q
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| q | every (quaque) | |
| Q.D. | every day (daily); also written QD, q.d., qd | Do Not UseJoint Commission Do Not Use (all variants: Q.D., QD, q.d., qd): the period after the Q can be mistaken for I, so it is read as QID, and it is confused with Q.O.D. Write "daily". |
| Q.O.D. | every other day; also written QOD, q.o.d., qod | Do Not UseJoint Commission Do Not Use (all variants: Q.O.D., QOD, q.o.d., qod): can be mistaken for Q.D. (daily) or QID if the O is read as a period. Write "every other day". |
| qhs | every night at bedtime | AmbiguousError-prone (ISMP): mistaken for qhr (every hour). Write "nightly at bedtime". |
| QID | four times daily (quater in die) | |
| qSOFA | Quick Sequential Organ Failure Assessment |
R
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| RA | Rheumatoid arthritis; right atrium; room air | AmbiguousRheumatoid arthritis, right atrium and room air are all common; context decides. |
| RAI | Radioactive iodine | |
| RAS | renal artery stenosis | AmbiguousRenal artery stenosis in nephrology; also reticular activating system (neurology) and renin-angiotensin system. Context decides. |
| RBBB | right bundle branch block | |
| RBC | Red blood cell count | |
| RCA | right coronary artery | |
| RCT | randomised controlled trial | |
| RDW | Red cell distribution width | |
| RF | Rheumatoid factor | |
| ROS | Review of systems | AmbiguousAlso reactive oxygen species in biochemistry; in clinical notes it means review of systems. |
| ROSC | Return of spontaneous circulation | |
| RR | respiratory rate | |
| RRT | renal replacement therapy | |
| RSI | Rapid sequence induction | |
| RSV | Respiratory syncytial virus | |
| RTA | Road traffic accident | AmbiguousAlso renal tubular acidosis in nephrology; in emergency care it usually means road traffic accident. |
| RV | right ventricle | |
| Rx | prescription or treatment (recipe) |
S
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| SAH | subarachnoid haemorrhage | |
| SBP | Spontaneous bacterial peritonitis; systolic blood pressure | AmbiguousSpontaneous bacterial peritonitis in cirrhosis; systolic blood pressure in general clinical notes. |
| SC | subcutaneous | AmbiguousError-prone (ISMP): SC and SQ have been mistaken for SL (sublingual). Write "subcut" or "subcutaneously". |
| SCD | Sickle cell disease | |
| SDH | subdural haematoma | |
| SGLT2 | Sodium-glucose cotransporter 2 | |
| SH | Social history | AmbiguousSocial history in history-taking; also sexual health or sinus histiocytosis in other contexts. |
| SIADH | Syndrome of inappropriate antidiuretic hormone secretion | |
| SIRS | Systemic inflammatory response syndrome | |
| SL | sublingual | |
| SOB | Shortness of breath | |
| SOFA | Sequential Organ Failure Assessment | |
| SPECT | Single-photon emission computed tomography | |
| SpO2 | peripheral oxygen saturation (pulse oximetry) | |
| SQ | subcutaneous (SQ or sub-Q) | AmbiguousError-prone (ISMP): mistaken for SL (sublingual) or "5 every". Write "subcut" or "subcutaneously". |
| SS | sliding scale (insulin) or half (semis) | AmbiguousAmbiguous (ISMP): sliding scale, or the Latin semis (one half); mistaken for 55. Write "sliding scale" or "one-half". |
| SSI | Surgical site infection | |
| SSRI | selective serotonin reuptake inhibitor | |
| STAT | immediately (statim) | |
| STEMI | ST-elevation myocardial infarction | |
| STI | Sexually transmitted infection | |
| SVD | Spontaneous vaginal delivery | |
| SVR | systemic vascular resistance | |
| SVT | supraventricular tachycardia | |
| Sx | symptoms |
T
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| T1DM | Type 1 diabetes mellitus | |
| T2DM | Type 2 diabetes mellitus | |
| T3 | Triiodothyronine | |
| T4 | Thyroxine | |
| TAH-BSO | Total abdominal hysterectomy with bilateral salpingo-oophorectomy | |
| TAVI | transcatheter aortic valve implantation | |
| TB | Tuberculosis | |
| TBI | traumatic brain injury | |
| TEE | Transoesophageal echocardiography | |
| TFT | Thyroid function tests | |
| THR | Total hip replacement | |
| TIA | transient ischaemic attack | |
| TIBC | Total iron-binding capacity | |
| TID | three times daily (ter in die) | |
| TIPS | Transjugular intrahepatic portosystemic shunt | |
| TIVA | Total intravenous anaesthesia | |
| TIW | three times a week | AmbiguousError-prone (ISMP): mistaken for twice a week (BIW) or three times a day (TID). Write "3 times weekly". |
| TKR | Total knee replacement | |
| TLC | total lung capacity | |
| TOE | transoesophageal echocardiography | |
| TOF | tetralogy of Fallot | |
| TORCH | Toxoplasma, other, rubella, cytomegalovirus, herpes (congenital infections) | |
| TPN | total parenteral nutrition | |
| TPO-Ab | Thyroid peroxidase antibodies | |
| TRAb | Thyrotropin receptor antibodies | |
| TRH | Thyrotropin-releasing hormone | |
| TSH | Thyroid-stimulating hormone | |
| TTE | transthoracic echocardiography | |
| TTP | Thrombotic thrombocytopenic purpura | |
| TURP | transurethral resection of the prostate | |
| Tx | treatment | |
| TXA | Tranexamic acid |
U
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| U | unit (written U or u) | Do Not UseJoint Commission Do Not Use (U and u): can be mistaken for 0, 4 or cc, causing a ten-fold or greater overdose. Write out "unit". |
| U&E | Urea and electrolytes | |
| UA | Urinalysis | |
| UC | Ulcerative colitis | |
| UFH | unfractionated heparin | |
| UGIB | Upper gastrointestinal bleeding | |
| UMN | upper motor neuron | |
| UO | urine output | |
| URTI | Upper respiratory tract infection | |
| US | Ultrasound | AmbiguousAlso read as United States in non-clinical text; in clinical notes it usually means ultrasound. |
| UTI | urinary tract infection |
V
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| V/Q | Ventilation-perfusion (scan or ratio) | |
| VAP | Ventilator-associated pneumonia | |
| VF | ventricular fibrillation | |
| VRE | Vancomycin-resistant enterococci | |
| VSD | ventricular septal defect | |
| VT | ventricular tachycardia | |
| VTE | Venous thromboembolism | |
| VUR | vesicoureteric reflux | |
| VWD | Von Willebrand disease | |
| VZV | Varicella-zoster virus |
W
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| WBC | White blood cell count | |
| WNL | Within normal limits | |
| WPW | Wolff-Parkinson-White syndrome |
X
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| X.0 mg | trailing zero after the decimal point (e.g. 1.0 mg) | Do Not UseJoint Commission formatting rule for medication orders: a trailing zero can be missed so that 1.0 mg is read as 10 mg (ten-fold overdose). Never write a trailing zero for doses expressed in whole numbers. |
#
| Abbreviation | Meaning | Safety flags |
|---|---|---|
| .X mg | lack of a leading zero before the decimal point (e.g. .5 mg) | Do Not UseJoint Commission formatting rule for medication orders: a missed decimal point can turn .5 mg into 5 mg (ten-fold overdose). Always write a zero before the decimal point (0.5 mg). |
| µg | microgram | AmbiguousError-prone (ISMP): the symbol µ is mistaken for mg (milli-), a 1000-fold overdose. Write "mcg". |
Do Not Use / Ambiguous
“Do Not Use” marks entries on The Joint Commission’s official Do-Not-Use list (a US accreditation standard for medication orders). “Ambiguous” marks abbreviations with several meanings or a record of misreading; other lists such as the ISMP list of error-prone abbreviations overlap with these. Local rules differ: when in doubt, write the full term.
References
- Official "Do Not Use" List of Abbreviations. The Joint Commission — Tier 2 (guidelines / primary literature)
- List of Error-Prone Abbreviations, Symbols, and Dose Designations. Institute for Safe Medication Practices — Tier 2 (guidelines / primary literature)
- Dorland's Illustrated Medical Dictionary. Elsevier — Tier 3 (textbook)
- International Classification of Diseases, 11th Revision (ICD-11). World Health Organization — Tier 1 (standards / international bodies)
References are listed only where the article cites them. See the sources page for the full policy. How sources are chosen and credited