Which laboratory test is routinely used to calculate the anion gap?

Which laboratory test is routinely used to calculate the anion gap?

• A. Electrolyte panel
• B. Complete blood count
• C. Coagulation panel
• D. Liver function panel

Answer: (A)

Anion gap calculation relies on specific electrolytes measured in routine labs: sodium, chloride, and bicarbonate. The formula is sodium minus (chloride plus bicarbonate). Because you need those three values, you obtain them from an electrolyte panel, which is typically included in a basic metabolic panel or comprehensive metabolic panel. A CBC, coagulation panel, or liver function panel does not include all of these electrolytes, so they aren’t used to compute the anion gap. In practice, clinicians pull Na, Cl, and HCO3- from a BMP or CMP to determine the anion gap, which helps assess metabolic acidosis and the presence of unmeasured anions.

Anion gap calculation relies on specific electrolytes measured in routine labs: sodium, chloride, and bicarbonate. The formula is sodium minus (chloride plus bicarbonate). Because you need those three values, you obtain them from an electrolyte panel, which is typically included in a basic metabolic panel or comprehensive metabolic panel. A CBC, coagulation panel, or liver function panel does not include all of these electrolytes, so they aren’t used to compute the anion gap. In practice, clinicians pull Na, Cl, and HCO3- from a BMP or CMP to determine the anion gap, which helps assess metabolic acidosis and the presence of unmeasured anions.