Multiple Myeloma and the Anion Gap

Abstract

THE anion gap (serum sodium - [chloride + bicarbonate]), represents those anions, other than chloride or bicarbonate, that counterbalance the positive charge of sodium. It is normally ≤ 14 mEq per liter. A high anion gap occurs in certain metabolic acidoses as a result of the replacement of bicarbonate by anions other than chloride. A low or negative anion gap could theoretically occur if additional cations other than sodium caused the retention of additional chloride and bicarbonate or both. It has been postulated that the low or negative anion gap, reported in a few patients with multiple myeloma, is due . . .