Bilirubin is a yellowish pigment produced during the breakdown of old red blood cells. It's a crucial substance that passes through the liver and is eventually eliminated from the body. Elevated bilirubin levels can signal various liver or bile duct issues.
Understanding Bilirubin: A Deeper Dive
Bilirubin is a byproduct of heme, the iron-containing molecule in hemoglobin, the protein that carries oxygen in red blood cells. When red blood cells reach the end of their lifespan (approximately 120 days), they are broken down, releasing heme. Heme is then converted into bilirubin.
The liver plays a vital role in processing bilirubin. It takes up unconjugated (indirect) bilirubin from the bloodstream, modifies it, and excretes it as conjugated (direct) bilirubin in bile. Bile, in turn, helps digest fats and is released into the intestines before ultimately being eliminated from the body in feces.
Why is Bilirubin Testing Important?
A bilirubin test measures the amount of bilirubin in your blood. This test is a key component of liver function tests, providing valuable insights into liver health.
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High Bilirubin Levels: High levels, often indicative of hyperbilirubinemia, can be caused by various factors, including:
- Liver diseases (hepatitis, cirrhosis)
- Bile duct obstructions (gallstones)
- Pancreatitis
- Certain cancers
- Excessive red blood cell breakdown (hemolysis)
- Gilbert's syndrome (a genetic condition affecting bilirubin processing)
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Low Bilirubin Levels: Lower than usual levels are typically not a cause for concern.
The type of bilirubin (direct or indirect) measured can further help pinpoint the underlying cause of abnormal levels. For example, higher levels of direct bilirubin may suggest a problem with the liver's ability to excrete bilirubin.
Several reliable sources confirm this information including the Cleveland Clinic (https://my.clevelandclinic.org/health/diagnostics/17845-bilirubin), MedlinePlus (https://medlineplus.gov/lab-tests/bilirubin-blood-test/), and Mayo Clinic (https://www.mayoclinic.org/tests-procedures/bilirubin/about/pac-20393041). Additional information can also be found on Ada Health (https://ada.com/biomarkers/bilirubin/), WebMD (https://www.webmd.com/a-to-z-guides/bilirubin-test), and the NCBI Bookshelf (https://www.ncbi.nlm.nih.gov/books/NBK470290/).
