When calculating the corrected anion gap, what change occurs with each 1 g/dL decrease in albumin?

When calculating the corrected anion gap (AG), it is essential to consider the influence of serum albumin levels on the anion gap measurement. The anion gap is calculated using the formula: AG = Na+ - (Cl- + HCO3-). This formula measures the concentration of unmeasured anions in the blood, which can be affected by the concentration of albumin.

Albumin is a negatively charged protein in serum, and it contributes to the overall anion balance. When albumin levels decrease, there are fewer negative charges present in the serum, which leads to a reduction in the anion gap value. Specifically, for each 1 g/dL decrease in albumin, the anion gap typically decreases by about 2.5 to 3 mmol/L.

This correction is crucial for interpreting the anion gap accurately, especially in patients with hypoalbuminemia, as it allows clinicians to better assess conditions such as metabolic acidosis. By adjusting the AG based on albumin levels, healthcare providers can avoid misdiagnosing acid-base disorders that could otherwise be masked by low albumin levels.