Bilirubin, Total
A yellow pigment made when old red blood cells break down. Your liver clears it, so the level reflects red cell turnover and bile flow.
AI-verified against cited sources. Awaiting expert reviewAlso called TBIL, T BILI, TSBLOINC 1975-2
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What it is
Bilirubin is a yellow-orange pigment made when old red blood cells are broken down. It travels to the liver, which changes it so it can leave your body in bile. Total bilirubin adds two forms together: unconjugated (indirect) bilirubin on its way to the liver and conjugated (direct) bilirubin that the liver has processed. When too much builds up in the blood, the skin and the whites of the eyes can turn yellow. This is called jaundice.
Why it matters
Total bilirubin shows how well your body balances making bilirubin from red cell breakdown and clearing it through the liver and bile ducts. A high level can be linked to faster red cell breakdown, liver conditions or blocked bile flow. The most common reason for a mild, isolated rise is Gilbert syndrome, a harmless inherited trait. Your clinician reads bilirubin together with your other liver tests and, if needed, direct and indirect bilirubin.
If it’s low
A low bilirubin is not usually a cause for concern.
Common causes
- Some medicines, such as certain antibiotics, birth control pills, sleeping pills and seizure medicines
What can help
- A low result on its own usually needs no action. You can mention it to your clinician if you take any of these medicines.
If it’s high
A level above your lab's range is often mild and has a harmless explanation, such as Gilbert syndrome or fasting. Higher levels can be linked to red blood cell breakdown, liver conditions or a blocked bile duct. Your other liver tests, and whether the rise is mostly the direct or the indirect form, help show which.
Common causes
- Gilbert syndrome, a common and harmless inherited trait that causes mild rises, especially when fasting or sick
- Fasting or eating very little (a fast of 36 hours or more can raise it)
- Red blood cells breaking down faster than usual (hemolysis)
- Reabsorption of a large bruise or collection of blood (hematoma)
- Medicines that affect the liver or bile flow
- Liver conditions such as hepatitis or cirrhosis, including alcohol-related liver disease
- A blocked bile duct, for example by a gallstone
- Rare inherited conditions such as Dubin-Johnson or Crigler-Najjar syndrome
What can help
- Ask your clinician whether direct and indirect bilirubin, a blood count, or a repeat test (sometimes after fasting) would help explain the result
- Review your medicines and supplements with your clinician
- If Gilbert syndrome is the explanation, ask how fasting or illness might affect your future results
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
The usual range depends on age. Choose an age to see the one that applies.
- 18+0–1.2 mg/dL
Sources: Labcorp, Mayo Clinic Laboratories, American Board of Internal Medicine
Children and teens 1 ranges
- 1–170–1.2 mg/dL
Sources: Labcorp, Mayo Clinic Laboratories
See Total bilirubin by age and sex, with the U.S. survey numbers where they exist.
If this applies to you
Total bilirubin means a little more for some people. Open the one that fits you.
Fatty liver or liver condition
Bilirubin, albumin and the clotting test INR give information on how well the liver is working, BSG notes. A raised bilirubin on its own, with other liver tests in range, is most often Gilbert syndrome, an inherited trait that BSG says is not linked to liver disease or ill health.
How common is your level?
NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.
Use the left and right arrow keys to read each age. Shift moves five years.
Reference data derived from CDC/NCHS National Health and Nutrition Examination Survey (NHANES), cycles 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. Analysis by bloodtesttracker.com; not endorsed by CDC, NCHS or HHS.
Explore Total bilirubin by age and sex: every percentile as a table, with a download.
What can affect your result
- Fasting or skipping meals, especially if you have Gilbert syndrome
- Illness and strenuous exercise
- Age: newborns have their own age-in-hours charts, and the adult range doesn't apply to them
- Light: bilirubin breaks down in light, so labs shield the sample
- Medicines and some foods
- Lab differences: Labcorp prints 0.0–1.2 mg/dL for ages 1 month and older, while Mayo prints 0.0–1.0 mg/dL for ages 15 days to 17 years and 0.0–1.2 for adults
- Bilirubin breaks down in light, so labs shield the sample from light during collection, storage and shipping (Mayo, ARUP).
- Fasting for 36 hours or more can cause a moderate rise (Labcorp), and the rise can be larger in Gilbert syndrome.
- Strenuous exercise, some medicines and some foods can raise bilirubin (MedlinePlus). Illness can also raise it, especially in Gilbert syndrome.
- Grossly hemolyzed or very fatty (lipemic) samples are rejected by labs (Labcorp).
- Serum should be separated from cells within about 45 minutes (Labcorp).
- A number of drugs can raise bilirubin, either by affecting the liver or by interfering with the lab method (Labcorp).
Unconjugated bilirubin can rise after a long fast (36 hours or more, per Labcorp) or during illness. After a liver or bile flow problem is resolved, bilirubin falls in two steps: a quick drop, then a slower one over weeks, because part of it is bound to albumin (Giannini 2005).
When to talk to a clinician
Contact your clinician soon if your skin or eyes look yellow, your urine is dark, your stools are pale, or you have belly pain, itching or fever, especially with a high result. Some lab lists treat a total bilirubin of 15 mg/dL (about 257 µmol/L) or more as urgent: Quest for children 2 and under, Michigan Medicine for newborns, and ARUP above 15 mg/dL at any age. A baby with yellow skin or eyes should be checked promptly by the baby's clinician, because safe levels depend on the baby's age in hours. Call 911 or your local emergency number for confusion, severe belly pain or fainting.
Questions you could ask
- If my bilirubin is mildly high on its own, which other tests would help?
- Does fasting or being sick change my results, and should I tell the lab or draw station?
- Would direct and indirect bilirubin, or a repeat test, help explain this result?
- Could a medicine or supplement be involved?
- Do my other liver tests and my blood count give any clues?
- Could one of my medicines explain a low bilirubin?
Questions people ask
Does a high bilirubin mean I have liver disease?
Not necessarily. A mild rise with otherwise normal liver tests is often Gilbert syndrome, a harmless inherited trait that affects roughly 5% to 8% of people. Faster red blood cell breakdown, fasting and some medicines can also raise it. Higher levels, especially with raised liver enzymes, yellow skin or dark urine, deserve a closer look with your clinician.
What is Gilbert syndrome?
It is an inherited trait in which the liver is a little slower than usual at processing bilirubin. Total bilirubin runs mildly high, mostly the indirect form, while other liver tests are normal. Levels can go up when you fast or are sick. It isn't linked to liver damage, and clinicians usually reach it by ruling out other causes.
Why did my bilirubin rise when I was fasting or sick?
Going without food for 36 hours or more can cause a moderate rise in bilirubin, and illness can too. The rise is usually larger in people with Gilbert syndrome. Clinicians sometimes repeat the test on a fasting sample to see whether the indirect part increases.
What is the difference between total, direct and indirect bilirubin?
Total bilirubin is the sum of two parts. Indirect (unconjugated) bilirubin is on its way to the liver. Direct (conjugated) bilirubin has been processed by the liver and is on its way out in bile. Which part is raised helps your clinician judge whether the cause is more likely red cell breakdown or the liver and bile ducts. We list direct and indirect bilirubin as their own markers.
My baby's bilirubin result looks high next to the adult range. Is that a problem?
Newborns normally have higher bilirubin than adults, and the level that matters depends on the baby's age in hours. Doctors compare a baby's result with age-in-hours charts, not a single range. Ask your baby's clinician what level applies at your baby's age and what the next step is.
Show the science and sources
Units
- 1 mg/dL = 1 mg/dL
- 1 mg/dL = 17.1 µmol/L
- 1 mg/dL = 10 mg/L
Open the Total bilirubin unit converter
Is a change real?
Total bilirubin naturally varies about 20.9% from test to test in the same healthy person. Between two results from the same lab, a rise of 78% or more, or a fall of 44% or more, is unlikely to be day-to-day noise or lab variation (95% reference change value). Source: The European Biological Variation Study (EuBIVAS): a summary report.
For clinicians and researchers
Bilirubin (C33H36N4O6, MW about 585) comes mostly from heme catabolism in the reticuloendothelial system. Unconjugated bilirubin is water-insoluble and albumin-bound, and hepatocytes conjugate it with glucuronic acid (UGT1A1) for excretion in bile. In healthy people conjugated bilirubin is nearly absent from serum, so a rise in the conjugated fraction usually points to liver or bile duct disease. Persistent conjugated bilirubin can bind albumin covalently (delta bilirubin), taking on albumin's roughly 20-day half-life, which explains the two-phase fall after recovery. Total bilirubin is measured by colorimetric or spectrophotometric methods (Mayo and Labcorp list colorimetric, ARUP spectrophotometry), and samples must be protected from light. In adults, unconjugated hyperbilirubinemia is most often hemolysis or Gilbert syndrome (reduced UGT1A1 activity, typically a promoter TA-repeat variant, affecting about 5% to 8% of people); indirect bilirubin in Gilbert syndrome usually stays below about 68 µmol/L (about 4 mg/dL). The BSG 2018 guideline advises repeating an isolated raised bilirubin with fractionation, a blood count and a fasting sample, and considering rarer causes such as Crigler-Najjar syndrome when unconjugated bilirubin exceeds 40 µmol/L. Conjugated bilirubin above 25 µmol/L in a neonate or infant needs urgent paediatric assessment. Newborn total serum bilirubin is interpreted against nomograms by hours of age (the 2022 AAP guideline; Mayo points to bilitool.org), not against adult intervals. Reference intervals differ slightly between labs.
LOINC 1975-2 (primary), 14631-6, 35194-0, 77137-8, 42719-5. Specimen: serum-or-plasma.
Sources
- Bilirubin, Total (test 001099), Labcorp
- Pediatric Testing Reference Ranges, Labcorp (2022)
- Comprehensive Metabolic Panel, Serum (test ID CMAMA), Mayo Clinic Laboratories
- Liver Profile, Serum (test ID LIVPR), Mayo Clinic Laboratories
- Bilirubin, Total, Serum or Plasma (test 0020032), ARUP Laboratories
- Critical Values List (CORP-APPEND-0104A, Rev. 46), ARUP Laboratories (2026)
- Quest Diagnostics Priority Result Reporting Policy (Client Synopsis), Quest Diagnostics (2025)
- Critical Value Policy, Michigan Medicine Laboratories (MLabs) (2025)
- ABIM Laboratory Test Reference Ranges (January 2026), American Board of Internal Medicine (2026)
- Guidelines on the management of abnormal liver blood tests, Gut (British Society of Gastroenterology) (2018)
- Liver enzyme alteration: a guide for clinicians, Canadian Medical Association Journal (2005)
- Bilirubin Blood Test, MedlinePlus, National Library of Medicine
- Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation, Pediatrics (American Academy of Pediatrics) (2022)
- Bilirubin (PubChem CID 5280352), PubChem, National Library of Medicine
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.