In uncomplicated hemolytic anemia serum bilirubin may be normal, or a minimal elevation of indirect bilirubin may be present; indirect (unconjugated) bilirubin does not readily pass through the glomerulus. Therefore, bilirubin is not usually detectable in the urine in uncomplicated hemolytic anemia. Because serum total bilirubin is not always increased with advanced liver disease, urine bilirubin may not be present in that circumstance. If jaundice is severe, renal excretion becomes significant; and if renal function deteriorates, serum direct bilirubin levels may increase. Urine bilirubin, if positive, implies an elevated serum conjugated (direct) bilirubin, which should be confirmed by serum measurement.