Bilirubin is a substance produced by the liver that can be found in the blood. It is normal to find bilirubin in the body; however, according to Medline Plus, excessive amounts of bilirubin in the blood may be an indicator of a medical condition or chemical imbalance somewhere in the body.
Significance of Direct Vs Indirect Bilirubin
The Mayo Clinic distinguishes between direct and indirect bilirubin: indirect bilirubin is created naturally when red blood cells break down, while direct bilirubin has passed through the liver and connected with sugars. It is the direct bilirubin that is stored in the gall bladder before it is excreted, along with the other waste from the body. The causes of elevated bilirubin vary based on which type of bilirubin is detected, though both types are tallied into the total bilirubin level.
Identification of an Elevated Level
According to the Mayo Clinic, bilirubin results usually include total bilirubin as well as direct bilirubin levels. A normal result for total bilirubin is 0.1 to 1.9 mg/dL, while a direct bilirubin should range between 0 and 0.3 mg/dL. The Mayo Clinic reports that results may vary a bit from test to test, and may be influenced by recent food ingestion as well as gender. This is why there appears to be such a range of "normal" levels.
Possible Causes in Adults
Elevated levels of bilirubin in adults typically reflect a problem either with the liver or with the destruction of blood cells. According to the Mayo Clinic, high levels may indicate some type of liver disease or dysfunction. This includes hepatitis and chronic alcohol use. There are several potential causes of high bilirubin levels. These include hemolytic disease, which affects the red blood cells, anemia and a healing hematoma, or pocket of blood under the skin, among others. Because there are so many possible causes, further tests may be performed to identify the cause of elevated bilirubin. According to the Mayo Clinic, these include tests for particular enzymes, a total blood count and protein levels.
Causes in Infants
It is not uncommon for new infants to have jaundice, which is caused by high levels of bilirubin. The American Association for Clinical Chemistry, or AACC, reports that almost half of all newborns have high bilirubin levels. Infants are born with extra red blood cells and an immature liver, both of which cause excessive amounts of bilirubin to collect in the blood. This usually resolves within a few days of birth; however, the AACC reports that high bilirubin levels in some infants may be an indication of incompatible blood types between mom and baby.
Warning
The AACC reports that while high levels of bilirubin in adults and older children are not necessarily life threatening, they may be a symptom of a more serious medical problem. It is a good idea to follow up with a doctor after any abnormal results on a bilirubin test.
