Total bilirubin in the body is comprised of which components?

Total bilirubin in the body consists of both conjugated and unconjugated bilirubin. To understand this, it's important to know what each component refers to.

Unconjugated bilirubin, also known as indirect bilirubin, is the form that is produced from the breakdown of hemoglobin in red blood cells. This form is not water-soluble and is transported in the blood bound to albumin. It is taken up by the liver, where it undergoes a process called conjugation.

Conjugated bilirubin, or direct bilirubin, refers to the bilirubin that has been processed in the liver and is now water-soluble. This form can be excreted into bile and ultimately eliminated from the body through the intestine.

Given this context, when total bilirubin is measured in clinical settings, it accounts for the sum of both the conjugated and unconjugated forms, allowing for a comprehensive assessment of bilirubin metabolism and liver function. This is vital for diagnosing various conditions, such as liver diseases or hemolytic anemias, where levels of these components can provide essential information about the patient's health status.