Total bilirubin

Bilirubin is a yellow pigment formed when haemoglobin from ageing red blood cells breaks down; the liver removes it through bile. Total bilirubin is the sum of unconjugated and conjugated forms and shows how blood, liver and bile ducts work together. It is most often measured alongside other liver tests and for jaundice.

Who is this test for

• people with yellow skin or whites of the eyes, dark urine or pale stools;
• people having a comprehensive check-up, alongside AST, ALT, GGT and alkaline phosphatase;
• people with suspected liver or bile duct disease and those treated for these diseases, for monitoring;
• people with suspected increased red blood cell breakdown (haemolysis);
• people taking medicines that may affect the liver.

What total bilirubin shows

Bilirubin occurs in blood in two forms:

• unconjugated (indirect) bilirubin forms through haemoglobin breakdown, is not water-soluble and travels through blood bound to albumin to the liver;
• conjugated (direct) bilirubin forms in the liver, is water-soluble and is excreted through bile into the intestine, giving stools their brown colour.

When total bilirubin is high, a doctor usually also requests direct bilirubin, while indirect bilirubin is calculated as total minus direct bilirubin. The predominant form indicates whether the cause lies in blood, liver or bile ducts.

Panels including this test

Test Total bilirubin is also included in this panel.

Extended liver health panelAST, ALT, AP, GGT, total bilirubin, total protein17.00€Details ›

All panels including Total bilirubin (11) ›

Preparation and sample

Bilirubin is measured in venous blood. Fasting is not essential for bilirubin alone, but if glucose or lipids are tested from the same collection, come fasting. Do not fast longer than a usual overnight fast: prolonged fasting, strenuous exercise and insufficient fluids may temporarily raise bilirubin, particularly in Gilbert syndrome. Tell your doctor which medicines you take.

How results are interpreted

Bilirubin is expressed in micromoles per litre (µmol/L). The reference interval depends on age and method; the interval printed on your report applies. In adults it is most often around 3 to 20 µmol/L. Yellowing of the eyes and skin usually becomes visible when bilirubin exceeds approximately 35 to 50 µmol/L.

Mildly high bilirubin and Gilbert syndrome

The most common reason for mildly elevated, predominantly unconjugated bilirubin in an otherwise healthy person is Gilbert syndrome. This is a common, harmless inherited condition in which the liver processes bilirubin more slowly. Bilirubin occasionally rises, particularly after fasting, with infection, exertion or lack of sleep, sometimes causing slight yellowing of the eyes. Other liver tests and blood count are normal. Gilbert syndrome does not damage the liver and is not treated, but tell your doctor you have it because it can affect tolerance of some medicines.

High unconjugated bilirubin

Besides Gilbert syndrome, causes include increased red blood cell breakdown (haemolytic anaemia), breakdown of a large bruise or some medicines. When haemolysis is suspected, a doctor requests complete blood count, reticulocytes and LDH.

High conjugated bilirubin

When conjugated bilirubin predominates, the cause usually lies in the liver or bile ducts: viral or alcoholic hepatitis, cirrhosis, drug-induced liver injury, gallstones or narrowing and obstruction of bile ducts. Other liver tests are often abnormal too, so a doctor interprets the result alongside them and may request ultrasound.

Jaundice in a newborn

Mild jaundice in the first days of life is common and usually resolves by itself. Contact a paediatrician if jaundice appears within the first 24 hours, is pronounced, lasts longer than two weeks (three weeks in premature babies), or stools are pale and urine dark.

When to seek urgent medical attention

Jaundice with abdominal pain, fever or chills requires urgent examination because it may indicate bile duct infection. Also seek urgent care for jaundice accompanied by confusion, drowsiness, bleeding or vomiting blood.

How to arrange testing

You can come for blood collection without an appointment or referral at one of our branches throughout Croatia (listed on the Contactpage). Prices for all tests and panels are listed in the service price list. Total bilirubin is part of the Extended Liver Health Panel, alongside AST, ALT, AP, GGT and total proteins.

Frequently asked questions

What does bilirubin in urine mean?

Only conjugated bilirubin can enter urine, making it dark like tea. This suggests liver or bile duct disease, not Gilbert syndrome or haemolysis. Urine bilirubin is shown by urine dipstick testing, and this finding should be shown to a doctor.

What does high indirect bilirubin mean?

Most often Gilbert syndrome, particularly if the increase is mild and other findings normal. Less commonly, increased red blood cell breakdown is responsible, so a doctor may request a blood count and reticulocytes.

Is high bilirubin dangerous?

It depends on the cause. A mild increase with otherwise normal findings is usually harmless. A greater increase, jaundice, dark urine or abnormal liver tests require medical examination and further investigation.