Bilirubin: normal range, high and low

In shortA common adult range for total bilirubin is 0.1–1.2 mg/dL (1.71–20.5 µmol/L). High values cause jaundice and point to the liver, the bile ducts, or increased red cell breakdown.

Reference ranges

Group	Reference range
Total bilirubin, adults	0.1–1.2 mg/dL (1.71–20.5 µmol/L)
Direct (conjugated) bilirubin	Less than 0.3 mg/dL (less than 5.1 µmol/L)

Ranges vary slightly between labs, and they differ by sex and by age. In newborns the level is normally higher for the first few days of life; how fast it rises, whether the baby was born early, and the baby's age all matter when a newborn's value is judged.

Check your value

Enter the number from your lab report — see how it compares with the typical range. Mind the units shown in the chosen row.

A rough comparison with a typical range, not a diagnosis. Reference ranges vary between laboratories — check the range on your own report and let a clinician interpret the result.

What this marker is

Bilirubin is a yellowish pigment found in bile, a fluid made by the liver. Every day a small share of older red blood cells is replaced by new ones, and bilirubin is what remains after those old cells are removed. The liver processes the pigment so that it can leave the body in the stool.

The test reports total bilirubin, and often its two fractions: direct (conjugated) bilirubin, which the liver has already processed, and indirect (unconjugated) bilirubin, which it has not. The split between the two fractions helps the provider decide where in the chain — red cells, liver, or bile ducts — the problem sits. Results are reported in milligrams per deciliter (mg/dL); in micromoles per liter (µmol/L) in many countries.

Jaundice — a yellow color in the skin, mucous membranes, or eyes — is the most common reason to check bilirubin, and a blood level around 2.0 mg/dL (about 34 µmol/L) can produce it. The test is also ordered when the provider suspects liver or gallbladder problems, and it is a routine check in newborns, because most newborns have some jaundice in the first days of life.

For the draw, a blood sample is taken from a vein. Your provider may ask you not to eat or drink beforehand and to pause medicines that affect the test — many medicines can change the bilirubin level, so the provider needs to know everything you take.

When it is high

Hemolytic anemiaWhen more red blood cells than normal are broken down, bilirubin production outruns the liver's capacity. Transfusion reactions and the newborn blood disorder erythroblastosis fetalis act the same way.

HepatitisA swollen and inflamed liver processes bilirubin poorly, so the pigment backs up into the blood.

Cirrhosis and other liver diseaseScarring of the liver and other liver diseases reduce the organ's ability to clear bilirubin.

Gilbert syndromeIn this inherited trait the liver does not process bilirubin in the usual way, producing mild rises without liver damage.

Blocked bile ductsGallstones, an abnormal narrowing of the common bile duct (biliary stricture), and cancers of the pancreas or gallbladder can dam the flow of bile and raise bilirubin.

When it is low

Usually not a concernLow bilirubin levels are not usually a cause for concern.

Certain medicinesMedicines such as antibiotics, birth control pills, sleeping pills, and seizure medicines may push bilirubin below the usual range.

What can skew the result

These factors can shift the value without any disease — worth considering before a retest:

Certain medicinesCertain foodsStrenuous exercise

How to prepare

Your provider may instruct you not to eat or drink before the test and to pause medicines that affect it. Many medicines can change the bilirubin level, so give the provider your full medication list.

When a retest makes sense

A result outside the lab's reference range usually leads to further testing, with the total value read together with its direct and indirect fractions and the liver enzymes.

Who usually reviews this result

A result outside the reference range is usually reviewed by: your GP or primary care doctor; a gastroenterologist or hepatologist if liver or bile duct disease is suspected. Bring your lab report and any previous results to the appointment.

Names used on lab reports

Your report may use any of these names:
Total bilirubinTBILTSBDirect bilirubinIndirect bilirubinConjugated bilirubinUnconjugated bilirubin

Units and conversion

Measured in: mg/dL

mg/dL = µmol/L

mg/dL × 17.1 = µmol/L. Example: 1.0 mg/dL = 17.1 µmol/L. Results are rounded to 2 decimal places.

Several markers on your report?

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Frequently asked questions

What is the difference between direct and indirect bilirubin?

Indirect (unconjugated) bilirubin is the form released when old red blood cells are removed; the liver then converts it into direct (conjugated) bilirubin so it can leave the body in bile. Which fraction is raised helps locate the problem: red cell breakdown, the liver itself, or the bile ducts.

Why do newborns get bilirubin tests?

Most newborns have some jaundice, because bilirubin is normally higher in the first days of life. Providers weigh how fast the level is rising, whether the baby was born early, and the baby's age when deciding whether a newborn's value is too high.

Can bilirubin be high without serious disease?

Yes. Gilbert syndrome is an inherited processing variant that produces mild rises without liver damage. Some medicines, certain foods, and strenuous exercise can also push the level up.

Sources

Bilirubin Blood Test: MedlinePlus Medical Test — MedlinePlus, National Library of Medicine. Accessed: August 29, 2026.
Bilirubin blood test: MedlinePlus Medical Encyclopedia — MedlinePlus, National Library of Medicine. Accessed: August 29, 2026.

Bilirubin