Hemobilirubin

A blood bilirubin test measures the amount of bilirubin in a blood sample. Bilirubin is a bile pigment produced when the liver breaks down old red blood cells. Bilirubin is then excreted in the feces, giving them their normal color. When bilirubin levels are too high, the skin and whites of the eyes may turn yellow (jaundice). Jaundice can be caused by liver diseases (hepatitis), blood disorders (hemolytic anemia), or blocked bile ducts. Bilirubin exists in two forms in the blood: Indirect bilirubin (unconjugated bilirubin): This form of bilirubin is not water-soluble and travels through the blood to the liver, where it is converted into water-soluble bilirubin (direct bilirubin or conjugated bilirubin). Direct bilirubin (conjugated bilirubin): Direct bilirubin is water-soluble and is formed in the liver from indirect bilirubin. Total bilirubin and direct bilirubin levels can be measured directly in the blood, while indirect bilirubin levels are derived from the measurements of total and direct bilirubin. Clinically, measuring bilirubin levels in the blood can help detect certain blood or liver diseases.