Description
Hemoglobin in urine; "Intravascular hemolysis results in hemoglobinemia when the amount of Hb released into plasma exceeds the Hb-binding capacity of plasma-binding protein haptoglobin, a protein normally present in concentrations of about 100 mg/dL (1 g/L) in plasma. . . . Hemoglobinuria results when reabsorptive capacity is exceeded." [Merck Manual, p. 1103]