Not medically reviewed
Normal lab values
Not medically reviewed · Content last updated · 6 min read ·
This is the date the draft was written, not a medical review date.
Typical adult reference intervals for about seventy common analytes, in conventional and SI units, with standard causes of high and low results.
Pick a laboratory group below to compare adult reference ranges in conventional and SI units, then open a test for the causes of high and low values. The ranges are generic: your laboratory’s own reference interval always applies.
Arterial blood gas interpretation — A stepwise guide with Winter’s formula, anion gap and delta-delta.
Haematology
| Analyte | Conventional units | SI units |
|---|---|---|
| Haemoglobin | Men: 13.5–17.5 g/dL Women: 12–15.5 g/dL | Men: 135–175 g/L Women: 120–155 g/L |
| Haematocrit | Men: 41–53 % Women: 36–46 % | Men: 0.41–0.53 L/L Women: 0.36–0.46 L/L |
| Red blood cell count | Men: 4.5–5.9 x10^6/µL Women: 4.1–5.1 x10^6/µL | Men: 4.5–5.9 x10^12/L Women: 4.1–5.1 x10^12/L |
| Mean corpuscular volume | 80–100 fL | 80–100 fL |
| Mean corpuscular haemoglobin | 27–33 pg | 27–33 pg |
| Mean corpuscular haemoglobin concentration | 32–36 g/dL | 320–360 g/L |
| Red cell distribution width | 11.5–14.5 % | 11.5–14.5 % |
| White blood cell count | 4–11 x10^3/µL | 4–11 x10^9/L |
| Neutrophils (absolute count) | 1.8–7.5 x10^3/µL | 1.8–7.5 x10^9/L |
| Lymphocytes (absolute count) | 1–4 x10^3/µL | 1–4 x10^9/L |
| Platelet count | 150–400 x10^3/µL | 150–400 x10^9/L |
| Reticulocyte count | 0.5–2.5 % of red cells | 0.005–0.025 fraction of red cells |
| Vitamin B12 (cobalamin) | 200–900 pg/mL | 148–664 pmol/L |
| Folate (vitamin B9) | 3–17 ng/mL | 6.8–38.5 nmol/L |
Electrolytes
| Analyte | Conventional units | SI units |
|---|---|---|
| Sodium | 135–145 mEq/L | 135–145 mmol/L |
| Potassium | 3.5–5 mEq/L | 3.5–5 mmol/L |
| Chloride | 98–107 mEq/L | 98–107 mmol/L |
| Bicarbonate (total CO2) | 23–29 mEq/L | 23–29 mmol/L |
| Calcium (total) | 8.5–10.5 mg/dL | 2.12–2.62 mmol/L |
| Calcium (ionised) | 4.6–5.3 mg/dL | 1.15–1.32 mmol/L |
| Magnesium | 1.7–2.2 mg/dL | 0.7–0.91 mmol/L |
| Phosphate (inorganic) | 2.8–4.5 mg/dL | 0.9–1.45 mmol/L |
Renal
| Analyte | Conventional units | SI units |
|---|---|---|
| Urea / blood urea nitrogen | 7–20 mg/dL (BUN) | 2.5–7.1 mmol/L (urea) |
| Creatinine | Men: 0.7–1.3 mg/dL Women: 0.6–1.1 mg/dL | Men: 62–115 µmol/L Women: 53–97 µmol/L |
| Uric acid | Men: 3.4–7 mg/dL Women: 2.4–6 mg/dL | Men: 202–416 µmol/L Women: 143–357 µmol/L |
Liver
| Analyte | Conventional units | SI units |
|---|---|---|
| Alanine aminotransferase (ALT) | 10–40 U/L | 10–40 U/L |
| Aspartate aminotransferase (AST) | 10–40 U/L | 10–40 U/L |
| Alkaline phosphatase (ALP) | 40–129 U/L | 40–129 U/L |
| Gamma-glutamyl transferase (GGT) | Men: 9–50 U/L Women: 8–40 U/L | Men: 9–50 U/L Women: 8–40 U/L |
| Total bilirubin | 0.1–1.2 mg/dL | 1.7–20.5 µmol/L |
| Direct (conjugated) bilirubin | 0–0.3 mg/dL | 0–5.1 µmol/L |
| Albumin | 3.5–5 g/dL | 35–50 g/L |
| Total protein | 6–8.3 g/dL | 60–83 g/L |
Lipids
| Analyte | Conventional units | SI units |
|---|---|---|
| Total cholesterol | < 200 mg/dL | < 5.2 mmol/L |
| LDL cholesterol | < 100 mg/dL | < 2.6 mmol/L |
| HDL cholesterol | Men: 40–60 mg/dL Women: 50–80 mg/dL | Men: 1.03–1.55 mmol/L Women: 1.29–2.07 mmol/L |
| Triglycerides | < 150 mg/dL | < 1.7 mmol/L |
Glucose
| Analyte | Conventional units | SI units |
|---|---|---|
| Fasting plasma glucose | 70–99 mg/dL | 3.9–5.5 mmol/L |
| Glycated haemoglobin (HbA1c) | 4–5.6 % (NGSP/DCCT) | 20–38 mmol/mol (IFCC) |
Coagulation
| Analyte | Conventional units | SI units |
|---|---|---|
| Prothrombin time | 11–13.5 seconds | 11–13.5 seconds |
| International normalised ratio | 0.8–1.2 ratio | 0.8–1.2 ratio |
| Activated partial thromboplastin time | 25–35 seconds | 25–35 seconds |
| Fibrinogen | 200–400 mg/dL | 2–4 g/L |
| D-dimer | < 500 ng/mL FEU | < 0.5 mg/L FEU |
Cardiac
| Analyte | Conventional units | SI units |
|---|---|---|
| High-sensitivity cardiac troponin (hs-cTn) | < 14 ng/L | < 14 ng/L |
| Creatine kinase MB isoenzyme (CK-MB mass) | < 5 ng/mL | < 5 µg/L |
| B-type natriuretic peptide (BNP) | < 100 pg/mL | < 100 ng/L |
| N-terminal pro-B-type natriuretic peptide (NT-proBNP) | < 300 pg/mL | < 300 ng/L |
Thyroid
| Analyte | Conventional units | SI units |
|---|---|---|
| Thyroid-stimulating hormone (TSH) | 0.4–4 mIU/L | 0.4–4 mIU/L |
| Free thyroxine (free T4) | 0.8–1.8 ng/dL | 10.3–23.2 pmol/L |
| Free triiodothyronine (free T3) | 2.3–4.2 pg/mL | 3.5–6.5 pmol/L |
Blood gases
| Analyte | Conventional units | SI units |
|---|---|---|
| Arterial blood pH | 7.35–7.45 pH units | 7.35–7.45 pH units |
| Partial pressure of arterial oxygen (PaO2) | 75–100 mmHg | 10–13.3 kPa |
| Partial pressure of arterial carbon dioxide (PaCO2) | 35–45 mmHg | 4.7–6 kPa |
| Arterial bicarbonate (HCO3-) | 22–26 mEq/L | 22–26 mmol/L |
| Base excess | -2–2 mEq/L | -2–2 mmol/L |
| Lactate | 4.5–18 mg/dL | 0.5–2 mmol/L |
| Arterial oxygen saturation (SaO2) | 95–100 % | 0.95–1 fraction |
| Anion gap | 8–12 mEq/L | 8–12 mmol/L |
Urinalysis
| Analyte | Conventional units | SI units |
|---|---|---|
| Urine pH | 4.5–8 pH units | 4.5–8 pH units |
| Urine specific gravity | 1.003–1.03 ratio | 1.003–1.03 ratio |
| Urine albumin-to-creatinine ratio (ACR) | < 30 mg/g | < 3.4 mg/mmol |
Iron and vitamins
| Analyte | Conventional units | SI units |
|---|---|---|
| Serum iron | Men: 59–158 µg/dL Women: 37–145 µg/dL | Men: 10.6–28.3 µmol/L Women: 6.6–25.9 µmol/L |
| Total iron-binding capacity (TIBC) | 250–450 µg/dL | 44.8–80.6 µmol/L |
| Ferritin | Men: 24–336 ng/mL Women: 11–307 ng/mL | Men: 24–336 µg/L Women: 11–307 µg/L |
| Transferrin saturation | 20–50 % | 0.2–0.5 fraction |
Inflammation
| Analyte | Conventional units | SI units |
|---|---|---|
| C-reactive protein (CRP) | < 5 mg/L | < 5 mg/L |
| Procalcitonin (PCT) | < 0.1 ng/mL | < 0.1 µg/L |
| Erythrocyte sedimentation rate (ESR) | Men: 0–15 mm/h Women: 0–20 mm/h | Men: 0–15 mm/h Women: 0–20 mm/h |
Endocrine
| Analyte | Conventional units | SI units |
|---|---|---|
| Serum cortisol (morning) | 6–23 µg/dL | 165–635 nmol/L |
| Parathyroid hormone (PTH) | 15–65 pg/mL | 15–65 ng/L |
| 25-hydroxyvitamin D | 20–50 ng/mL | 50–125 nmol/L |
Other
| Analyte | Conventional units | SI units |
|---|---|---|
| Lactate dehydrogenase (LDH) | 125–220 U/L | 125–220 U/L |
| Amylase | 30–110 U/L | 30–110 U/L |
| Lipase | < 160 U/L | < 160 U/L |
References
- Rifai N, Horvath AR, Wittwer CT. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Elsevier, 6th edition (2018) — Tier 3 (textbook)
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. Elsevier — Tier 3 (textbook)
- EP28-A3c: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline, Third Edition. Clinical and Laboratory Standards Institute, 3rd edition (2010) — Tier 2 (guidelines / primary literature)
- Loscalzo J, et al.. Harrison's Principles of Internal Medicine. McGraw-Hill, 21st edition (2022) — Tier 3 (textbook)
References are listed only where the article cites them. See the sources page for the full policy. How sources are chosen and credited