Also Known As
Total Bilirubin
Neonatal Bilirubin
Direct Bilirubin
Conjugated Bilirubin
Indirect Bilirubin
Unconjugated Bilirubin
Formal Name
Bilirubin - blood
This article was last reviewed on
This article waslast modified on March 24, 2021.
At a Glance
Why Get Tested?

To screen for or monitor liver disorders or hemolytic anemia; to monitor neonatal jaundice

When To Get Tested?

When you have signs or symptoms of liver damage, liver disease, bile duct blockage, hemolytic anemia, or a liver-related metabolic problem, or if a newborn has jaundice

Sample Required?

In adults, a blood sample is drawn from a vein. In newborns, a blood sample is often collected by pricking the heel of the infant and collecting a few drops of blood in a small tube (heelstick). Non-invasive technology is available in some healthcare facilities that will measure bilirubin by using an instrument placed on the skin (transcutaneous bilirubin meter).

Test Preparation Needed?


What is being tested?

Bilirubin is an orange-yellow pigment, a waste product primarily produced by the normal breakdown of heme. Heme is a component of hemoglobin, which is found in red blood cells (RBCs). Bilirubin is ultimately processed by the liver so that it can be removed from the body. This test measures the amount of bilirubin in the blood to evaluate a person's liver function or to help diagnose anemias caused by RBC destruction (hemolytic anemia).

RBCs normally degrade after about 120 days in circulation. Bilirubin is formed as the liver breaks down and recycles aged red blood cells.

Two forms of bilirubin can be measured or estimated by laboratory tests:

  • Unconjugated bilirubin is formed when heme is released from hemoglobin. It is carried by proteins to the liver. In the liver, sugars are attached (conjugated) to bilirubin to form conjugated bilirubin.
  • Conjugated bilirubin enters the bile and passes from the liver to the small intestines, where it is further broken down by bacteria and eventually eliminated in the stool. Thus, the breakdown products of bilirubin give stool its characteristic brown color. Normally, the level of conjugated bilirubin in the blood is very low.

The bilirubin test is included in the comprehensive metabolic panel (CMP) and the liver panel, which are often used as general health screenings.

  • Usually, an initial test measures the total bilirubin level (unconjugated plus conjugated bilirubin).
  • If the total bilirubin level is increased, the laboratory can use a second test to detect water-soluble forms of bilirubin, called "direct" bilirubin. The direct bilirubin test provides an estimate of the amount of conjugated bilirubin present.
  • Subtracting the direct bilirubin level from the total bilirubin level helps estimate the "indirect" level of unconjugated bilirubin.

A small amount (approximately 250 to 350 milligrams, or about 4 milligrams per kilogram of body weight) of bilirubin is produced daily in a normal, healthy adult. Most bilirubin (70%-90%) comes from damaged or degraded RBCs, with the remaining amount coming from the bone marrow or liver. Normally, small amounts of unconjugated bilirubin are released into the blood, but almost no conjugated bilirubin is present.

If the bilirubin level increases in the blood, a person may appear jaundiced, with a yellowing of the skin and/or whites of the eyes. The pattern of bilirubin test results can give the healthcare practitioner information regarding the condition that may be present. (For details, see "What does the test result mean?" under Common Questions.)

Accordion Title
Common Questions
  • How is the test used?

    A bilirubin test may be used as part of a comprehensive metabolic panel (CMP) during a routine health exam to evaluate the health of your liver. It may also be used either alone or as part of a liver panel to detect an increased level in the blood to help determine the cause of jaundice and/or help diagnose conditions such as liver disease, hemolytic anemia, and blockage of the bile ducts.

    In adults and older children, bilirubin is measured to:

    • Help diagnose and/or monitor diseases of the liver and bile duct (e.g., cirrhosis, hepatitis, or gallstones)
    • Evaluate people with sickle cell disease or other causes of hemolytic anemia; these people may have episodes called crises when large numbers of red blood cells (RBCs) are destroyed and bilirubin levels increase.

    In newborns with jaundice, bilirubin is used to distinguish the causes of jaundice.

    • In both physiologic jaundice of the newborn and hemolytic disease of the newborn, only unconjugated (indirect) bilirubin is increased.
    • In much less common cases, damage to the newborn's liver from neonatal hepatitis and biliary atresia will increase conjugated (direct) bilirubin and unconjugated (indirect) bilirubin, often providing the first evidence that one of these less common conditions is present.

    It is important that an elevated level of bilirubin in a newborn be identified and quickly treated because excessive unconjugated bilirubin damages developing brain cells. The consequences of this damage include mental retardation, learning and developmental disabilities, hearing loss, eye movement problems, and death.

  • When is it ordered?

    A healthcare practitioner may order a bilirubin test along with other laboratory tests (e.g., CMP, liver panel) when you have a routine health exam or when you have signs and symptoms of liver damage or disease, such as:

    • Jaundice
    • Dark, amber-colored urine
    • Nausea/vomiting
    • Abdominal pain and/or swelling
    • Fatigue and general malaise that often accompany chronic liver disease

    A bilirubin level may also be ordered when you have:

    • A history of drinking excessive amounts of alcohol
    • Signs and symptoms of drug toxicity
    • Been exposed to a virus that causes hepatitis

    Measuring and monitoring bilirubin in newborns with jaundice is considered standard medical care.

    Tests for bilirubin may also be ordered when you have or are suspected of having hemolytic anemia. In this case, it is often ordered along with other tests used to evaluate the breakdown of red blood cells, such as complete blood count, reticulocyte count, haptoglobin, direct antiglobulin test (DAT) and lactate dehydrogenase (LD, LDH).

  • What does the test result mean?

    Adults and children

    Total bilirubin that is mainly unconjugated (indirect) bilirubin may be increased when:

    • There is an unusual number of red blood cells (RBCs) being broken down and destroyed (e.g., hemolytic or pernicious anemia, blood transfusion reaction)
    • The liver is unable to process bilirubin (i.e., with liver disease such as cirrhosis or inherited problems)
    • You have a relatively common inherited condition called Gilbert syndrome, due to low levels of the enzyme that produces conjugated bilirubin

    If conjugated (direct) bilirubin is elevated more than unconjugated (indirect) bilirubin, there typically is a problem associated with decreased elimination of bilirubin by the liver cells. Some conditions that may cause this include:

    • Viral hepatitis (hepatitis A, hepatitis B, hepatitis C)
    • Drug reactions
    • Alcoholic liver disease

    Conjugated (direct) bilirubin is also elevated more than unconjugated (indirect) bilirubin when the liver is able to process bilirubin but there is blockage of the bile ducts. This may occur, for example, with:

    • Gallstones present in the bile ducts
    • Tumors
    • Scarring of the bile ducts

    Rare inherited disorders that cause abnormal bilirubin metabolism such as Rotor, Dubin-Johnson, and Crigler-Najjar syndromes, may also cause increased levels of bilirubin.

    Low levels of bilirubin are generally not a concern and are not monitored.


    Increased total and unconjugated bilirubin levels are relatively common in newborns in the first few days after birth. This finding is called "physiologic jaundice of the newborn" and occurs because the newborn's liver is not mature enough to process bilirubin yet. Usually, physiologic jaundice of the newborn is temporary and resolves within a few days to two weeks.

    However, if the bilirubin level is critically high or increases rapidly, the healthcare practitioner will diagnose the cause so appropriate treatment can be started as soon as possible.

    Increased bilirubin levels may result from the accelerated breakdown of red blood cells due to:

    In most of these conditions, only unconjugated (indirect) bilirubin is increased.

    A rare (about 1 in 12,000 births) but life-threatening congenital condition called biliary atresia can cause increased total and conjugated bilirubin levels in newborns. This condition must be quickly diagnosed and treated, usually with surgery, to prevent serious liver damage that may require liver transplantation within the first few years of life. Some children may require liver transplantation despite early surgical treatment.

  • Is there a urine test for bilirubin?

    Yes. Bilirubin testing is included as part of the common dipstick tests used in a routine urinalysis. Bilirubin is not normally present in the urine. However, conjugated bilirubin is water-soluble and may be eliminated from the body through the urine if it cannot pass into the bile. If bilirubin is detected in the urine, it usually means your liver or bile ducts are blocked or you have hepatitis or some other form of liver damage. In these cases, bilirubin may be detectable in the urine early in the disease.

  • Do some people have an inherited (genetic) risk of abnormal bilirubin levels?

    Yes, several inherited chronic conditions can increase bilirubin levels in the blood. These include:

    • Gilbert syndrome
    • Dubin-Johnson syndrome
    • Rotor syndrome
    • Crigler-Najjar syndrome

    The first three are usually mild, chronic conditions that can be aggravated under certain conditions but in general cause no significant health problems. For example, Gilbert syndrome is very common; about 1 in every 6 people has this genetic abnormality, but usually people with Gilbert syndrome do not have elevated bilirubin. Crigler-Najjar syndrome is the most serious inherited condition listed; this disorder is relatively rare, and some people with it may die.

  • How do you treat abnormal bilirubin levels and/or jaundice?

    Treatment depends on the cause of the jaundice. In newborns, phototherapy (special light therapy), blood exchange transfusion, and/or certain drugs may be used to reduce the bilirubin level. In Gilbert, Rotor, and Dubin-Johnson syndromes, no treatment is usually necessary. Crigler-Najjar syndrome may respond to certain enzyme drug therapy or may require a liver transplant. Jaundice caused by an obstruction is often resolved by surgery. Jaundice due to cirrhosis is a result of long-term liver damage and does not respond well to any type of therapy other than liver transplantation.

  • Is there anything else I should know?

    Though unconjugated bilirubin may be toxic to brain development in newborns (up to 2-4 weeks of age), it does not pose the same threat to older children and adults. In older children and adults, the "blood-brain barrier" is more developed and prevents bilirubin from moving from the blood into the brain and affecting brain cells. Nevertheless, elevated bilirubin strongly suggests that a medical condition is present that must be evaluated and treated.

    Bilirubin concentrations tend to be slightly higher in males than females. African Americans routinely show lower bilirubin concentrations than non-African Americans. Strenuous exercise may increase bilirubin levels.

    Drugs that can decrease total bilirubin include barbiturates, caffeine, penicillin, and high doses of salicylates. The drug atazanavir increases unconjugated (indirect) bilirubin.

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

For more information, please read the article Reference Ranges and What They Mean.

Health Professionals – LOINC

Logo for LOINC from RegenstriefLOINC Observation Identifiers Names and Codes (LOINC®) is the international standard for identifying health measurements, observations, and documents. It provides a common language to unambiguously identify things you can measure or observe that enables the exchange and aggregation of clinical results for care delivery, outcomes management, and research. Learn More.

Listed in the table below are the LOINC with links to the LOINC detail pages. Please note when you click on the hyperlinked code, you are leaving Lab Tests Online and accessing

LOINC LOINC Display Name
33898-8 Bilirubin.conjugated+indirect [Mass/Vol]
33899-6 Bilirubin.conjugated+indirect [Moles/Vol]
1971-1 Bilirubin.indirect [Mass/Vol]
14630-8 Bilirubin.indirect [Moles/Vol]
15152-2 Bilirubin.conjugated [Mass/Vol]
29760-6 Bilirubin.conjugated [Moles/Vol]
1968-7 [Mass/Vol]
43820-0 Ql
14629-0 [Moles/Vol]
1970-3 [Mass/Vol]
22665-4 [Moles/Vol]
42719-5 Bilirubin (Bld) [Mass/Vol]
59827-6 Bilirubin (BldA) [Mass/Vol]
59828-4 Bilirubin (BldV) [Mass/Vol]
1975-2 Bilirubin [Mass/Vol]
54363-7 Bilirubin (Bld) [Moles/Vol]
89872-6 Bilirubin (BldA) [Moles/Vol]
89871-8 Bilirubin (BldV) [Moles/Vol]
77137-8 Bilirubin (S/P/Bld) [Moles/Vol]
14631-6 Bilirubin [Moles/Vol]
58941-6 Bilirubin Transcutaneous meter (Skin) [Mass/Vol]
72898-0 Bilirubin Transcutaneous meter (Skin) [Moles/Vol]
View Sources

Sources Used in Current Review

(2018 January 19, Updated) Hemolytic Anemia. U.S. National Library of Medicine. Available online at Accessed October 2019.

Wehbi, Mohammad. (2015 January 14) Bilirubin. Medscape. Available online at Accessed October 2019.

Kalakonda, Aditya, Savio, John. (2019 May 5, Updated) Bilirubin, Physiology. National Center for Biotechnology Information. Available online at Accessed October 2019.

(2017 September, Updated) Definition and Facts of Biliary Atresia. National Institute of Diabetes and Digestive and Kidney Diseases. Available online at Accessed October 2019.

Hemolytic Disease of the Newborn. Children's Hospital of Philadelphia. Available online at Accessed October 2019.

(2018 April 9, Updated) What are Jaundice and Kernicterus? Centers for Disease Control and Prevention. Available online at Accessed October 2019.

Vitek, L. (2017 April 5) Bilirubin and Artherosclerotic Diseases. Physiological Research. Available online at Accessed October 2019.

Sources Used in Previous Reviews

The Cleveland Clinic. Jaundice (online information). Available online through Accessed March 2008.

KidsHealth, Nemours Foundation. Jaundice in Healthy Newborns (online information). Available online through Accessed March 2008.

Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006 Pp. 131-135.

(January 22, 2007) MedlinePlus. Bilirubin (online information). Available online at Accessed April 2008.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri.

Pagana K, Pagana T. Mosby's Diagnostic and Laboratory Test Reference. 5th Edition, St. Louis: Mosby, Inc.; 2001.

WebMD. Bilirubin. Available online through Accessed December 2005.

Pagana and Pagana. Mosby's Manual of Diagnostic and Laboratory Tests. 4th edition. Pp. 130-135.

MedlinePlus Medical Encyclopedia. Bilirubin – blood. Available online at Accessed January 2012. 

MedlinePlus Medical Encyclopedia: Biliary atresia. Available online at Accessed January 2012.

MedlinePlus Medical Encyclopedia. Newborn jaundice. Available online at Accessed January 2012. Bilirubin test. Available online at Accessed January 2012.

National Heart Lung Blood Institute. Hemolytic anemia. Available online at Accessed January 2012.

National Digestive Diseases Information Clearinghouse. Biliary Atresia. Available online at Accessed January 2012.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp 269-270.

2015 review performed by Danyel H. Tacker, PhD, DABCC, FACB, Technical Director, WVUH Laboratory Chemistry & Mass Spectrometry Sections.

Burtis, Carl A. & Bruns, David E. (Editors). (© 2015). Chapter 28: Hemoglobin, Iron, and Bilirubin. Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 7th Edition: Elsevier, St. Louis, MO. Pp 513-519.

Williamson, Mary A. & Snyder, L. Michael (Editors). (© 2015). Wallach's Interpretation of Diagnostic Tests: Pathways to arriving at a clinical diagnosis. 10th Edition: Wolters Kluwer, Philadelphia, PA. Pp 829-831.

McPherson, Richard A. & Pincus, Matthew R (Editors). (© 2011) Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd Edition: Elsevier, Philadelphia, PA. Pp 297-299.

(August 26, 2015). Jaundice. MedlinePlus (U.S. National Library of Medicine). Available online at Accessed on 9/8/2015.

(February 23, 2015) Facts about jaundice and kernicterus. Centers for Disease Control and Prevention. Available online at Accessed on 9/8/2015.

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