Bilirubin Test

Bilirubin is formed by the breakdown of red blood cells in the body. The liver helps to excrete it. High levels of bilirubin can lead to jaundice. This disorder is easily recognizable due to a yellowing of the skin and eyes. High bilirubin levels can occur in adults, but the disorder is more common in newborn infants. This is because it takes some time after birth for an infant to start efficiently metabolizing bilirubin and excreting it in their stool.

The approximate normal range of bilirubin in the blood serum is:

  • 1.2 milligrams per deciliter (mg/dL) for adults
  • 1 mg/dL for children under 18 years of age

The skin normally becomes yellow once levels reach between 2 and 3 mg/dL.

Any person who experiences yellowing of the skin or eyes should see their doctor. It may be a sign of a serious condition.

Testing Bilirubin

Blood tests can help identify excessive bilirubin.

Blood tests can measure bilirubin levels. While there is a urine test for bilirubin, it is less accurate and often falsely positive.

If a routine urine test detects bilirubin, a doctor will look at blood serum tests to confirm the results and identify any damage to the liver.

Other tests include:

  • further blood tests to assess liver function and test for hepatitis, if indicated
  • a physical exam, where a doctor may feel the abdominal area to see if the liver is enlarged or tender.
  • imaging tests to visualize the liver. These might include ultrasound, computerized X-ray with a CT scan, or high-powered images with an MRI scan.
  • an endoscopy is sometimes carried out to look at the ducts in which the bile travels to the gut.
  • a liver biopsy is sometimes needed, although this is uncommon. In this procedure, a small sample of liver tissue is sent to a lab for evaluation.

 High bilirubin levels

High bilirubin can lead to jaundice.A high level of bilirubin in the blood is known as hyperbilirubinemia.

High bilirubin levels can cause jaundice. Jaundice makes the skin and the whites of the eyes appear yellow, due to the brown and yellow bilirubin in the blood. There are several reasons for a rise in bilirubin levels outside the newborn period. These causes can occur before, during, or after the production of bilirubin.

What is bilirubin?

The breakdown of red blood cells (RBCs) in the body produces bilirubin. The bilirubin travels to the liver and is stored in the bile duct. The body ultimately expels bilirubin in stools.

The RBCs have a lifespan of around 120 days and renew continually. RBCs contain hemoglobin, which helps transport oxygen around the body, and it is this that gets broken down into bilirubin and other substances. The bilirubin is carried to the liver by albumin, a simple protein.

Once in the liver, bilirubin becomes “conjugated.” This means it becomes water-soluble and can be excreted.

Unconjugated bilirubin is toxic, but conjugated bilirubin is usually not, because it can be removed from the body, as long as nothing is interfering with its removal.

Before reaching the liver

Some conditions cause bilirubin levels to be high before it reaches the liver.

This is the pre-hepatic or “pre-liver” phase, and it can be caused by hemolytic anemia and the reabsorption of internal pools of blood by the body. Hemolytic anemia occurs when too many red blood cells are broken down before the end of their natural life cycle.

In the liver

If the liver is not working properly, it may be unable to make bilirubin water-soluble. This may result in too much bilirubin building up in the liver.

Causes include, but are not limited to the following: viruses, such as hepatitis A. alcoholic liver disease some medicine overdoses, including acetaminophen autoimmunity, where a disorder of the immune system causes it to attack the cells of the body rather than those that cause disease

Once the bilirubin has left the liver, levels may be high because the bilirubin is unable to leave the body. This may be a result of blockage in one of the other organs that assist excretion, such as gallstonesin the gallbladder. This is called the post-hepatic phase. Other causes include: inflammation or cancer of the gallbladder, which produces bilepancreatitis.

 Result Interpretation

A bilirubin test measures total bilirubin. It can also give levels of two different types of bilirubin: unconjugated and conjugated.

Unconjugated (“indirect”) bilirubin. This is the bilirubin created from red blood cell breakdown. It travels in the blood to the liver.

Conjugated (“direct”) bilirubin. This is the bilirubin once it reaches the liver and undergoes a chemical change. It moves to the intestines before being removed through your stool.

For adults over 18, normal total bilirubin can be up to 1.2 milligrams per deciliter (mg/dl) of blood. For those under 18, the normal level will be will be 1 mg/dl. Normal results for conjugated (direct) bilirubin should be less than 0.3 mg/dl.

Men tend to have slightly higher bilirubin levels than women. African-Americans tend to have lower bilirubin levels than people of other races.

High total bilirubin that is mostly unconjugated (indirect) may be caused by:

  • Anemia
  • Cirrhosis
  • A reaction to a blood transfusion
  • Gilbert syndrome — a common, inherited condition in which there is a deficiency of an enzyme that helps to break down bilirubin.
  • Viral hepatitis
  • A reaction to drugs
  • Alcoholic liver disease
  • Gallstones

Strenuous exercise can increase your bilirubin levels.

Caffeine, penicillin, barbiturates, and nonsteroidal anti-inflammatory drugs (NSAIDs) called salicylates all lower your bilirubin levels. Lower-than-normal levels of bilirubin aren’t usually a problem, but better to check with health provider.

In newborns, high bilirubin levels that don’t level out in a few days to 2 weeks may be a sign of:

  • Blood type incompatibility between mother and child
  • Lack of oxygen
  • An inherited infection
  • A disease affecting the liver

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EXTRA

A bilirubin test measures the amount of bilirubin in your blood. It’s used to help find the cause of health conditions like jaundice, anemia, and liver disease.

Bilirubin is an orange-yellow pigment that occurs normally when part of your red blood cells break down. Your liver takes the bilirubin from your blood and changes its chemical make-up so that most of it is passed through your poop as bile.

If your bilirubin levels are higher than normal, it’s a sign that either your red blood cells are breaking down at an unusual rate or that your liver isn’t breaking down waste properly and clearing the bilirubin from your blood.

Another option is that there’s a problem somewhere along the pathway that gets the bilirubin out of your liver and into your stool.

Why Do You Get This Test?

In children and adults, doctors use it to diagnose and monitor liver and bile duct diseases. These include cirrhosis, hepatitis, and gallstone help determine if you have sickle cell disease or other conditions that cause hemolytic anemia. That’s a disorder where red blood cells are destroyed faster than they’re made.

High levels of bilirubin can cause a yellowing of your skin and eyes, a condition doctors call jaundice.

High bilirubin levels are common in newborns. Doctors use the age of the newborn and the bilirubin type and levels to determine if treatment is necessary.

What Happens During the Test?

A nurse or lab technician will draw blood through a small needle inserted into a vein in your arm. The blood is collected in a tube.

With newborns, blood is usually drawn by using a needle to break the skin of the heel.

Your doctor will send the blood to a lab for analysis.

Before the test, tell your doctor about how active you’ve been and what food and medicines you’ve taken. Diet, medications, and exercise can alter your results.

After the test, you’ll be able to continue with your normal activities right away.

Who Should Get It? Who Shouldn’t?

Your doctor may order a bilirubin test if you:

  • Show signs of jaundice
  • Have anemia, or low red blood cells
  • Might be having a toxic reaction to drugs
  • Have a history of heavy drinking
  • Have been exposed to hepatitis viruses

You might also have your bilirubin tested if you have symptoms like:

  • Dark urine
  • Nausea and vomiting
  • Abdominal pain or abdominal swelling
  • Clay-colored stools
  • Fatigue

 

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