What is Direct Bilirubin?

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  • Written By: C. Stoliecki
  • Edited By: John Allen
  • Last Modified Date: 19 November 2018
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Bilirubin is a brownish-yellow pigment that is found in bile, which is a liquid secreted by the liver that allows the body to digest fats. There are two forms: direct and indirect. Direct bilirubin is often referred to as conjugated bilirubin, while indirect bilirubin is known as unconjugated bilirubin. The difference between them is that direct bilirubin is water-soluble, meaning that it can be dissolved in water, and indirect bilirubin is not.

Direct bilirubin production is the final step in a complex chain of events that occur as the body rids itself of the waste left over from old red blood cells. During the first stage, indirect bilirubin is produced within certain types of cells that reside in bone marrow, the liver, and the spleen. This happens as red-blood cells reach the end of their life cycles and begin to break down into their component parts. One of these component parts, heme, a reddish pigment, is further broken down to make indirect bilirubin.

Newly formed indirect bilirubin is then carried into the liver via water-soluble proteins known as albumin. In the liver, it becomes water-soluble when it reacts with a sugar based compound known as glucuronic acid. Once this occurs, direct bilirubin is formed. As soon as it becomes water soluble, the body prepares to remove it from the body.


Next, the bilirubin is mixed with the bile and transferred from the liver into the intestines and gall bladder. At this point, it is broken down into two of its component parts, known as stercobilin and urobilinogen. Stercobilin combines with other waste materials in the intestines and is excreted as part of the fecal matter. Urobilinogen is transported to the kidneys, where it becomes part of the waste that is expelled with the body’s urine.

There are several conditions that can result when bilirubin levels in the body become imbalanced. Jaundice, which can tint the skin a yellowish color, is a condition that occurs when bilirubin is produced at a faster rate than it is excreted from the liver. This can happen when too much is made or if the liver is unable to excrete it due to some malfunction. In some cases, the bile ducts, which are tubes that carry bile away from the liver, can become obstructed, causing the problem.


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Post 4

My friend has a condition called sickle cell anemia. Her red blood cells are sickle-shaped and fragile. Normal red blood cells live around 120 days, but hers die after ten to twenty days. Because red blood cell breakdown makes bilirubin, she has a high bilirubin level that often leads to gallstones.

She is constantly short on red blood cells, and without them, her body can’t get enough oxygen for energy. She feels tired all the time.

A bone marrow transplant is the only possible cure for this disease, and it is highly risky. For right now, she is just taking pain medication and getting blood transfusions. Sometimes, she has to take breathing treatments to get enough oxygen in her system.

Post 3

When my uncle went to his doctor complaining of abdominal swelling and pain, fatigue, nausea, and dark urine, the doctor tested his bilirubin levels. These were all signs of decreased liver function, and he would use the test to determine what was wrong with his liver. Since my uncle had a history of alcohol abuse, there was a good chance he had liver damage.

Bilirubin tests are used to check for jaundice, drug toxicity, and hepatitus viruses. The doctor told my uncle that he probably didn’t have jaundice, since his skin appeared a normal color. He also didn’t have any exposure to hepatitis, so it was likely that his alcohol consumption had damaged his liver.

When the doctor got the results, he determined that it was most likely cirrhosis. Further testing confirmed this.

Post 2

@wavy58 - It is so sad that people back away from a person with jaundice. They must think that it is contagious!

I knew a boy in high school with the condition. He was very yellow, but otherwise he was very attractive. He had maybe one or two friends and no girlfriend, because kids regarded him as weird or diseased.

Because of his social standing, he became very defensive, often lashing out when teased. He frequently got in fights. However, if you actually talked to him, you could see that he was sweet with a polite demeanor. I wish that everyone could have seen that side of him.

Post 1

Jaundice affected my cousin’s social life. He had trouble making new friends, because his yellow skin scared people. The whites of his eyes were also yellowish, and this put people off further.

Even though he had issues, he was one of the lucky ones. His bilirubin level was only slightly elevated. Some people with high bilirubin levels have brown skin and eyes.

My cousin joined a support group for people with jaundice. He met people who have hemolytic anemia, which is an extremely rapid destruction of blood cells that causes lots of bilirubin to be released into the blood. He also met people with gallstones and inflamed bile ducts that slowed the excretion of bilirubin from the liver.

He even met people like himself, who have a defective liver that can’t remove bilirubin as it should. He made many friends here.

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