Another name for the Indirect Bilirubin lab test is the Unconjugated bilirubin test. It’s measuring how much bilirubin you have in your blood. The source of the bilirubin in your blood is from the breakdown of hemoglobin in the red blood cells. It’s the job of your liver to detoxify bilirubin from your body.

This test is run routinely to see if patients have liver problems, especially cirrhosis of the liver. It’s also done when the doctor suspects that you have hemolytic anemia or pernicious anemia. One other time this test is run is when your total bilirubin blood test is showing abnormal levels.

Other times the Indirect Bilirubin test is run is when either a transfusion reaction is suspected or some genetic diseases (Rotor syndrome, Crigler-Najjar syndrome, Dubin-Johnson syndrome, or Gilbert syndrome) are suspected. 

Normal Ranges for Indirect Bilirubin in mg/dL:

To calculate Indirect bilirubin easily, take Total Bilirubin level and subtract the Direct Bilirubin level from it.

Total bilirubin: 0.3-1.9 mg/dL

Direct bilirubin: 0.0-0.3 mg/dL

Indirect bilirubin: 0.2-0.7 mg/dL (estimated range; you still have to do the calculation.)

Sources: 

1. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=indirect_bilirubin
2. https://www.mayoclinic.org/tests-procedures/bilirubin/about/pac-20393041
3. http://www.labpedia.net/test/26