American journal of nephrology
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The serum anion gap (serum [Na(+)]-Cl(-)]-[CO(2)]) is still the first-line approach to metabolic acidosis. However, while it is generally acknowledged that hypoalbuminemia mandates a downward adjustment of the expected anion gap, a specific correction factor for the anion gap in the face of low serum albumin has never been demonstrated. ⋯ For intensive care patients with normal or high serum tCO(2) (>21 mEq/l) a simple bedside adjustment of the anion gap by subtracting 1.5 times the difference between measured serum albumin and the 'normal' level of 4.0 g/dl gives a close estimate of the actual anion gap. For intensive care patients with serum tCO(2) <22 mEq/l, correction of the anion gap is well predicted by adding about twice the Delta (albumin) to the calculated gap.