What is the normal anion gap range without including potassium?

• A. 7-16 mmol/L
• B. 10-20 mmol/L
• C. 8-18 mmol/L
• D. 5-15 mmol/L

Answer: (A)

Anion gap is a calculated value that estimates unmeasured anions in the blood. It’s computed as the difference between the principal measured cation and the principal measured anions: Na minus (Cl plus HCO3). This helps differentiate causes of metabolic acidosis and is interpreted against a normal reference range.

When potassium is not included in the calculation, the normal range commonly cited in many laboratories is about 7 to 16 mEq/L. This broader range accounts for variability between labs and methods. The typical, more tightly cited figure without potassium is around 8 to 12 mEq/L, but 7–16 is a widely used alternative that fits the intended reference interval in many exam contexts.

So, among the given options, the range 7–16 aligns with the normal reference interval for the anion gap when potassium is not included. Values outside this range could suggest a metabolic acidosis with either accumulation of unmeasured anions or a loss of bicarbonate, depending on the direction of the deviation.