Value of Anion-Gap Determination in Multiple Myeloma

Abstract

Hyponatremia has frequently been observed in patients with multiple myeloma, in some being associated with a relative hyperchloremia.^{1 , 2} More recent investigations have shown that, in multiple myeloma, the anion gap is lowered as compared to normal controls,^{3 4 5 6} thereby confirming that the total anions are not decreased in the same proportion as the total cations. This low anion gap was accounted for by the presence of large amounts of circulating cationic paraproteins.³ However, none of these studies provided extensive documentation on the possible diagnostic value of the anion gap in multiple myeloma, nor did they provide data on the relation between . . .