Bilirubin where is it produced

About Search. Enable Autosuggest. You have successfully created a MyAccess Profile for alertsuccessName. Home Books Gastrointestinal Physiology, 2e. Previous Chapter. Next Chapter. AMA Citation Chapter Bilirubin Formation and Excretion by the Liver. In: Barrett KE. Barrett K. Kim E. Gastrointestinal Physiology, 2e. McGraw Hill; Accessed November 11, APA Citation Chapter Barrett KE. McGraw Hill. MLA Citation "Chapter Download citation file: RIS Zotero. Reference Manager.

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch. There is very little risk of a problem from a heel stick.

Your baby may get a small bruise at the puncture site. There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site. Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test.

The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

Normal values in newborns depend on the age of the baby in hours and whether the baby was premature or full term. Normal values may vary from lab to lab. Current as of: September 23, Thomas London MD - Hepatology. Author: Healthwise Staff. Medical Review: E. This information does not replace the advice of a doctor.

Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content. To learn more about Healthwise, visit Healthwise. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. Updated visitor guidelines. You are here Home » Bilirubin Test. Top of the page. Test Overview A bilirubin test measures the amount of bilirubin in a blood sample.

Bilirubin circulates in the bloodstream in two forms: Indirect or unconjugated bilirubin. Direct or conjugated bilirubin. Why It Is Done The bilirubin test is used to: Check liver function and watch for signs of liver disease, such as hepatitis or cirrhosis , or the effects of medicines that can damage the liver. Find out if something is blocking the bile ducts.

Biliverdin is converted into unconjugated bilirubin, which is transported in the bloodstream by binding with albumin and taken up by the liver. Conjugated bilirubin is then excreted in bile. Figure 2. The product is conjugated bilirubin, which can be excreted in bile. In the intestines, bacterial enzymes hydrolyze conjugated bilirubin to release free, unconjugated bilirubin, which is reduced to urobilinogen.

Urobilinogen, bound to albumin, is then excreted in urine. Figure 3. In the intestines, conjugated bilirubin is hydrolyzed by bacterial enzymes to produce unconjugated bilirubin and ultimately urobilinogen, which can be excreted in urine after binding to albumin. In the intestines, some urobilinogen is converted to stercobilinogen and excreted in the stool. Thus, in normal urine, only urobilinogen is present; in normal stool, only stercobilinogen is present.

Figure 4. Urobilinogen in the intestines can also be converted to stercobilinogen, which is then excreted in the stool. Cholestatic or obstructive jaundice occurs when liver cells are unable to transport bilirubin through the hepatic-bile capillary membrane because of damage in the liver. Obstructive jaundice can also occur when transport through the biliary tract is blocked because of anatomical obstructions such as gallstones or cancer. In obstructive jaundice, conjugated bilirubin regurgitates into the blood.

Because it is water-soluble, bilirubin is excreted into the urine. This is called choluria, or the presence of bile in the urine. As well, less conjugated bilirubin is taken up by the intestines in obstructive jaundice.

As a result, less stercobilinogen is found in the stool and the stool appears pale. Table 1.