Electrolytes

Chloride (Cl)

Source-checked · Content last updated 2026-10-07 · 1 min read ·

This is the date the draft was written, not a medical review date.

Chloride is the main extracellular anion and generally moves with sodium; it is mainly used in the anion gap and in the analysis of acid-base disorders.

Reference interval

	Conventional (mEq/L)	SI (mmol/L)
Adults	98–107 mEq/L	98–107 mmol/L

Specimen: Serum or plasma · Conventional × 1 = SI

Causes of high values

Hyperchloraemia: normal-saline loading, non-anion-gap metabolic acidosis (diarrhoea, renal tubular acidosis), dehydration and respiratory alkalosis.

Causes of low values

Hypochloraemia: vomiting or gastric drainage, diuretics, metabolic alkalosis, SIADH and chronic respiratory acidosis with renal compensation.

Pre-analytical and method notes

Reference limits vary slightly by laboratory (some print 96-106 mmol/L). Bromide, iodide and severe hyperlipidaemia can interfere with some methods; analysis on indirect ion-selective electrodes is affected by lipid and protein excess.

Related calculators

Serum Anion Gap (with albumin correction)

References

Rifai N, Horvath AR, Wittwer CT. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Elsevier, 6th edition (2018) — Tier 3 (textbook)
Loscalzo J, et al.. Harrison's Principles of Internal Medicine. McGraw-Hill, 21st edition (2022) — Tier 3 (textbook)

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