Bilirubin blood test

A bilirubin blood test checks liver health by measuring the levels of bilirubin (bil-ih-ROO-bin) in the blood. Bilirubin is produced when red blood cells are broken down and recycled.

The liver processes bilirubin into bile, which typically drains through the bile ducts into the intestine. Higher bilirubin levels can happen when this drainage is blocked, such as by gallstones or cancers of the liver or pancreas.

Sometimes, higher bilirubin levels happen when red blood cells break down at a faster rate, even if there's no blockage.

Bilirubin passes through the liver and eventually leaves the body in stool or urine. Higher than usual levels of bilirubin can cause a yellow color to the skin and eyes, called jaundice. Yellowing of the skin might be harder to see on some skin colors. Higher levels of bilirubin also can make the stools look light or clay-colored and urine look brown or orange.

Bilirubin blood testing is usually part of a group of tests to check the liver. These tests are known as liver function tests. Bilirubin blood testing may be done to:

• Find the cause of jaundice.
• Check the cause of other symptoms such as fever, chills, weight loss and feeling tired — especially if you also have pain in your upper right abdomen.
• Check for a blockage in the bile ducts in the liver or the gallbladder.
• Look for liver disease such as hepatitis or cancer. Testing also helps monitor disease progression.
• Help diagnose anemia caused by the destruction of red blood cells, called hemolysis. This happens when red blood cells break down sooner than they should.
• See how a treatment is working.
• Check if a medicine may be causing harm.

One common, but harmless, cause of raised bilirubin is Gilbert syndrome. Gilbert syndrome is a condition in which the liver processes bilirubin more slowly than average. Once you know that Gilbert syndrome is the cause of higher bilirubin on blood tests, you do not need to worry about it.

Sometimes, bilirubin levels temporarily rise with stresses such as dehydration, fasting and exercise.

Infant jaundice is another temporary, common condition. It is more common in babies born before 37 weeks of pregnancy, known as premature babies, and in some breastfed babies. Your healthcare professional may check your baby's bilirubin level in the first few days of life to make sure it doesn't get too high.

Most newborns born after 35 weeks of pregnancy need no treatment for jaundice. High levels of bilirubin that cause severe jaundice can cause serious complications if not treated.

A healthcare professional may order more tests to study your condition. Some tests that may be done at the same time as bilirubin blood testing include:

• Liver function tests. These blood tests measure certain enzymes and other proteins in the blood. Elevated enzymes may indicate damage to the liver or blockage of bile ducts. If the liver or bile ducts can't properly do their jobs, the bilirubin builds up in the body.
• Albumin and total protein. Albumin is a protein made by the liver. Albumin and total protein levels show how well the liver makes proteins that help the body fight infections and perform other functions.
• Complete blood count. This test measures several components and features of the cells in blood.
• Prothrombin time. This test measures the clotting time of plasma.

The blood sample for a bilirubin blood test typically is taken from a vein in the arm. For newborn infants, the blood sample typically is taken from the heel. For most people, a bilirubin blood test is quick and easy. There's little risk in getting a bilirubin blood test. As with any blood test, possible risks may include:

• Brief discomfort where the needle enters the skin.
• Soreness or tenderness in the area where the blood is taken.
• Bruising near the area where the blood is taken.
• Bleeding.
• Fainting or feeling lightheaded.
• Infection of the area where the blood is taken. This is rare.

If you feel dizzy, tell the person taking your blood right away. You need to rest until you feel better.

Most people don't need to do anything special to get ready for a bilirubin blood test. But there are some medicines, foods and drinks that could affect your test results. For this reason, tell your healthcare team about any medicines you take.

Your care team may ask you not to eat, drink or take any medicines before the test.

Before

Your healthcare team tells you where to go for your bilirubin blood test. The test may be done in your healthcare professional's office. It may be done in a clinic, hospital or lab. Or it may be done in your home.

During

To do the bilirubin blood test, a healthcare professional takes a small sample of your blood.

Typically, you sit in a chair for the test. The healthcare professional places a small needle into one of your veins, typically in your arm. You may feel a small pinch or sting when the needle goes in.

A small tube is attached to the needle to collect the blood. When your test is done, your healthcare professional puts a small bandage on your arm.

For newborns, most often the blood is collected using a sharp lancet to break the skin of the heel. This is known as a heel stick. The healthcare professional puts a small bandage on the heel.

The blood sample goes to a lab for analysis.

After

You might have a small bruise or feel sore where the needle went in. That usually goes away in a day or two. You typically can return to usual activities right away.

Bilirubin blood test results are expressed as indirect, direct or total bilirubin.

• Total bilirubin. This is a combination of direct and indirect bilirubin.
• Direct bilirubin. This type is produced by the liver. The bilirubin changes into a water-soluble form so the bilirubin can be carried in bile and removed from the body. The medical term for this form is conjugated bilirubin.
• Indirect bilirubin. This type is made when red blood cells break down, mostly in the spleen. The bilirubin binds to a protein called albumin and travels through the bloodstream to the liver. The medical term for this form is unconjugated bilirubin. Indirect bilirubin levels equal total bilirubin minus direct bilirubin.

Typically, the test results are for direct and total bilirubin. Typical results for a total bilirubin test are 1.2 milligrams per deciliter (mg/dL) for adults and 1 mg/dL for those under age18. Typical results for direct bilirubin are 0.3 mg/dL. There is no difference by age. But bilirubin levels often are slightly lower during pregnancy.

Lower bilirubin levels usually are not a concern. Higher levels of direct bilirubin may mean your liver isn't clearing bilirubin properly. This may mean there is liver damage or disease. Higher levels of indirect bilirubin may be a sign of other problems. Jaundice typically occurs when total bilirubin levels are higher than 3 mg/dL.

Adults

In adults, treatment for high bilirubin depends on the cause. If levels are high due to liver disease, cancer, infection or a blockage in the bile ducts, treatment focuses on managing that condition. Sometimes bilirubin levels improve by stopping certain medicines or alcohol.

Infants

In newborns, jaundice occurs when bilirubin levels rise but the baby's liver isn't mature enough to get rid of bilirubin. Mild jaundice often goes away on its own in two or three weeks. But higher levels of bilirubin need to be treated. If untreated, severe jaundice can lead to permanent brain damage.

A healthcare professional uses a device called a transcutaneous bilirubinometer to measure the reflection of a special light shone through your baby's skin. A bilirubin blood test checks your baby's bilirubin levels with blood taken from a heel.

Light therapy, also called phototherapy, is a common treatment for jaundice. Your baby may be placed under a special lamp that emits light in the blue-green spectrum. The light changes the shape and structure of bilirubin molecules in such a way that they can be eliminated in both the urine and stool. During therapy, your baby typically wears only a diaper and protective eye patches.