calculate_anion_gap: Serum Anion Gap

In cliot: Clinical Indices and Outcomes Tools

Serum Anion Gap

Description

Calculates the Serum Anion Gap (AG) to evaluate metabolic acidosis. The Anion Gap represents the difference between measured cations (Sodium) and measured anions (Chloride and Bicarbonate). An optional calculation for the Albumin-Corrected Anion Gap is included, which adjusts for hypoalbuminemia, a common cause of a falsely low anion gap.

Usage

calculate_anion_gap(sodium, chloride, bicarbonate, albumin = NULL)

Arguments

sodium	Numeric. Serum Sodium level in mEq/L or mmol/L.
chloride	Numeric. Serum Chloride level in mEq/L or mmol/L.
bicarbonate	Numeric. Serum Bicarbonate (or total CO2) level in mEq/L or mmol/L.
albumin	Numeric (Optional). Serum Albumin level in g/dL. Used to calculate the Corrected Anion Gap.

Details

The basic formula is:

AG = Na - (Cl + HCO3)

The Albumin-Corrected Anion Gap formula is:

Corrected AG = AG + (2.5 \times (4.4 - Albumin))

Normal Anion Gap range is typically considered 4-12 mEq/L, though this varies by laboratory assay.

Value

A list containing:

Anion_Gap	The calculated Anion Gap.
Corrected_Anion_Gap	The Anion Gap adjusted for albumin level (if albumin is provided).

References

Emmett M, Narins RG. Clinical use of the anion gap. Medicine (Baltimore). 1977;56(1):38-54. Figge J, Jabor A, Kazda A, Fencl V. Anion gap and hypoalbuminemia. Crit Care Med. 1998;26(11):1807-1810.

Examples

calculate_anion_gap(sodium = 140, chloride = 100, bicarbonate = 24)

calculate_anion_gap(sodium = 140, chloride = 100, bicarbonate = 24, albumin = 2.5)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.