Electrolytes & Minerals

Anion Gap

Normal range 8–16 mEq/L (8–16 mmol/L SI). Specimen: Serum or plasma (calculated).

Also known as: AG.

8–16 mEq/LReference range

Reference range

ConventionalmEq/L

816

SImmol/L

816

Specimen	Serum or plasma (calculated)
Conventional range	8–16 mEq/L
SI range	8–16 mmol/L
Conversion factor	×1 (conventional → SI)
Panel	Electrolytes & Minerals

Convert any Anion Gap result between units on the unit converter.

What is the normal range for Anion Gap?

The standard teaching reference range for Anion Gap is 8–16 mEq/L in conventional units, or 8–16 mmol/L in SI units. This value is measured in serum or plasma (calculated).

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high Anion Gap

Diabetic ketoacidosis
Lactic acidosis
Renal failure (uremia)
Toxic ingestions (salicylates, methanol)

Below the range

Common causes of a low Anion Gap

Hypoalbuminemia
Lab measurement variation

At the bedside

Nursing considerations

Calculated as Na⁺ − (Cl⁻ + HCO₃⁻).
A high gap points to accumulated acids — remember the MUDPILES causes.

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More Electrolytes & Minerals tests

Bicarbonate (CO₂ content)22–29 mEq/L Calcium, Ionized4.6–5.3 mg/dL Calcium, Total (Ca²⁺)8.6–10.2 mg/dL Chloride (Cl⁻)98–106 mEq/L Magnesium (Mg²⁺)1.6–2.6 mg/dL Phosphate (Phosphorus)2.5–4.5 mg/dL