The Peroxidase Activity of Hemoglobin on the Urinalysis

Dr. Fruke: I think something that really frustrates nephrologists is that the naming of this blood on the urinalysis because as you said, it's not really looking for blood. And so what that test really is doing is it's looking for peroxidase activity that hemoglobin possesses. In patients that have thrombotic micro angiopathy, that have intravascular hemolysis, what does that do that leads to free hemoglobin? So that's why we get low haptoglobin and then anything that is excess in the blood generally is going to be coming out in urine.