Anion Gap Normal — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

HardPhysiology - Endocrine & MetabolicAnion Gap NormalFRCA Primary

A patient has sodium 140 mmol/L, chloride 104 mmol/L and bicarbonate 24 mmol/L. What is the anion gap?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — 12 mmol/L

The best answer is “12 mmol/L”. The conventional anion-gap calculation is sodium minus chloride minus bicarbonate. Here, 140 − 104 − 24 equals 12 mmol/L. The reference range depends on the laboratory method and whether potassium is included, so the stated formula and values are essential.

Reference: RCoA, Primary FRCA Syllabus: https://rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf