La bilirubin is a Pigment not soluble in water of yellow color, resulting from the degradation ofhemoglobin. It is the main dye of bile. It is produced in the cells of the rates and bone marrow, and is then transported through the bloodstream by albumin to the liver. Once present in the liver, it is conjugated with gluconic acid and becomes soluble in water. In the intestines, conjugated bilirubin gives the stool a brown color.

The doctor will order a blood test for bilirubin if he suspects, for example:

• hepatobiliary disorders: conditions that affect the liver (hepatitis being the most common) and / or the bile ducts
• hemolytic syndromes (characterized by abnormal destruction of red blood cells)
• or jaundice of the newborn, also called jaundice of the newborn

For a bilirubin test, a blood test should be done, which consists of a venous blood test. It is recommended that you do not eat or drink at least 4 hours before the blood test. The doctor may also ask the patient to stop taking certain medicines that may affect the results of the bilirubin test.

The amount of total bilirubin in the blood is normally between 0,3 and 1,9 mg / dl (milligrams per deciliter). The amount of conjugated bilirubin (also called direct bilirubin) is normally between 0 and 0,3 mg / dl. 

Note that the so-called normal values ​​of bilirubin in the blood may vary depending on the laboratory performing the analyzes.

Only a doctor can interpret the results and give you a diagnosis.

If the bilirubin level is high, it is calledhyperbilirubinémie.

It can be a:

• predominance of the free form (by excess production or a lack of conjugation):

— accidents transfusionnels

– hemolytic anemias: toxic, medicinal, parasitic hemolysis, etc.

– Gilbert’s disease (genetic abnormality of bilirubin metabolism)

– jaundice of the newborn

– Criggler-Najjar syndrome (inherited disorder of bilirubin metabolism)

• predominance of the conjugated form (conjugated bilirubin is released into the circulation when the normal route of excretion is blocked):

– gallstone

– neoplasia (cancer)

– pancreatitis

– toxic hepatitis, alcoholic hepatitis, viral hepatitis

– cirrhosis

One distinguishes in particular the “jaundice with free bilirubin”, which are rather due to an excess of destruction of the red blood cells (hemolysis) of “the jaundice with conjugated bilirubin”, rather related to a biliary or hepatic disease.