Calculated Plasma/Serum Direct Bilirubin Index (from Indirect Bilirubin and Haptoglobin)

What This Test Measures

Your blood contains bilirubin, a yellow pigment produced when red blood cells break down. Indirect bilirubin is the form that circulates in your bloodstream before being processed by your liver. Haptoglobin is a protein that binds to free hemoglobin released when red blood cells are destroyed. This test uses these two measurements to calculate an index that reflects the balance between bilirubin production and liver processing capacity.

Why It Matters in Your Health

This calculation helps identify conditions where red blood cells break down too quickly (hemolysis), which can overwhelm your liver’s ability to process bilirubin, potentially leading to jaundice or other complications.

Common Conditions Monitored

Doctors may use this calculation to monitor conditions like hemolytic anemia, liver diseases, or certain blood disorders where red blood cell breakdown is abnormal.

What to Expect During Testing

This test involves a simple blood draw from a vein in your arm. No special preparation is needed, but fasting may be required depending on other tests ordered with it.