What is a Bilirubin blood test?

Email this page to a friend Print Facebook Twitter Pinterest The bilirubin blood test measures the level of bilirubin in the blood. Bilirubin is a yellowish pigment found in bile, a fluid made by the liver.
Bilirubin can also be measured with a urine test.

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

You should not eat or drink for at least 4 hours before the test. Your health care provider may instruct you to stop taking medicines that affect the test.
Many drugs may change the bilirubin level in your blood. Make sure your provider knows which medicines you are taking.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

A small amount of older red blood cells are replaced by new blood cells every day. Bilirubin is left in the blood after these older blood cells are removed. The liver helps break down bilirubin so that it can be removed from the body in the stool.
A level of bilirubin in the blood of 2.0 mg/dL can create jaundice. Jaundice is a yellow color in the skin, mucus membranes, or eyes.
Jaundice is the most common reason to check the bilirubin level. The test will likely be ordered when:

• The provider is concerned about a newborn's jaundice (most newborns have some jaundice)
• Jaundice develops in older infants, children, and adults

A bilirubin test is also ordered when the provider suspects a person has liver or gallbladder problems.

Normal Results

It is normal to have some bilirubin in the blood. A normal level is:

• Direct (also called conjugated) bilirubin: less than 0.3 mg/dL (less than 5.1 µmol/L)
• Total bilirubin: 0.1 to 1.2 mg/dL (1.71 to 20.5 µmol/L)

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

In newborns, the bilirubin level is higher for the first few days of life. Your child's provider must consider the following when deciding whether your baby's bilirubin level is too high:

• How fast the level has been rising
• Whether the baby was born early
• The baby's age

Jaundice can also occur when more red blood cells than normal are broken down. This can be caused by:

• A blood disorder called erythroblastosis fetalis
• A red blood cell disorder called hemolytic anemia
• Transfusion reaction in which red blood cells that were given in a transfusion are destroyed by the person's immune system

The following liver problems may also cause jaundice or a high bilirubin level:

• Scarring of the liver (cirrhosis)
• Swollen and inflamed liver (hepatitis)
• Other liver diseases
• Disorder in which bilirubin is not processed normally by the liver (Gilbert disease)

The following problems with gallbladder or bile ducts may cause higher bilirubin levels:

• Abnormal narrowing of the common bile duct (biliary stricture)
• Cancer of the pancreas or gallbladder
• Gallstones

Risks

There is little risk involved with having your blood taken. Veins vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Risks associated with having blood drawn are slight, but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood collecting under the skin)
• Infection (a slight risk any time the skin is broken)

Alternative Names

Total bilirubin - blood; Unconjugated bilirubin - blood; Indirect bilirubin - blood; Conjugated bilirubin - blood; Direct bilirubin - blood; Jaundice - bilirubin blood test; Hyperbilirubinemia - bilirubin blood test

What is Bilirubin Direct and Indirect ?

Also Known As: Total Serum Bilirubin TSB Total Bilirubin TBIL Neonatal Bilirubin Direct Bilirubin Conjugated Bilirubin Indirect Bilirubin Unconjugated Bilirubin

Formal Name: Bilirubin - blood

Bilirubin is a dark yellow waste product that is primarily created when the body breaks down hemoglobin, which is the protein in red blood cells that carries oxygen. Bilirubin is found in bile, which is fluid in your liver that is involved in digesting food. Most bilirubin is eliminated in the feces or urine.

The bilirubin test checks the health of your liver by measuring the amount of bilirubin in blood or in your urine. This can help diagnose or monitor problems related to your liver or red blood cells when the bilirubin level is too high.

Purpose of the test

Doctors often order a bilirubin test along with other tests performed on a single blood or urine sample, such as in a comprehensive metabolic panel, a liver panel, or a urinalysis.

Testing bilirubin in the blood and urine can help doctors diagnose problems such as jaundice, a condition that may cause your eyes and skin to turn yellow, as well as hepatitis, cirrhosis, gallbladder disease, and hemolytic anemia.

Bilirubin blood testing is also used to diagnose newborn jaundice which can lead to a condition called kernicterus at very high bilirubin levels. Prolonged and very high bilirubin levels can lead to complications if left untreated, so testing is commonly performed in newborns during their first few days of life and when signs of jaundice appear.

In people who have been diagnosed with a liver disorder, repeated bilirubin testing can help a doctor monitor the status of the patient’s disease and how they are responding to treatment.

What does the test measure?

The bilirubin blood test measures the amount of bilirubin in the blood. Results are commonly expressed as mg/dL, or milligrams of bilirubin per deciliter of blood.

Bilirubin mainly exists in two forms in the blood. Initially, bilirubin is “unconjugated.” Unconjugated bilirubin is bilirubin attached to albumin, the main protein in blood that carries substances to the liver.

In the liver, bilirubin undergoes a process called conjugation with a substance called glucuronide, through which bilirubin becomes “conjugated.” Conjugated bilirubin is water-soluble and ready to be excreted into bile.

A total bilirubin blood test includes unconjugated and conjugated bilirubin. Due to the uniqueness of the analytical measurement of bilirubin, unconjugated bilirubin may also be called indirect bilirubin while conjugated bilirubin may also be referred to as direct bilirubin.

Another less common bilirubin measurement, called delta bilirubin, is only formed when the excretion of conjugated bilirubin by the liver is impaired. This can happen when a patient suffers from a bile duct obstruction. This type of conjugated bilirubin is linked to albumin and may persist for a prolonged period of time in your blood.

Neonatal bilirubin is commonly assessed in newborns and refers to the marked elevation of total bilirubin mainly due to the increase in unconjugated bilirubin. Typically, a newborn’s liver needs a few days to take over the clearance of the bilirubin by conjugating bilirubin. This leads to increased bilirubin levels which then reach normal levels about one week after birth.

The urinary bilirubin test measures whether or not bilirubin is present in the urine.

How to get tested

Bilirubin testing is typically conducted in a medical setting after being ordered by a doctor.

If you are being evaluated for a liver condition or red blood cell disorder, your doctor may also order other tests, including blood or urine tests, an ultrasound, or a biopsy.