High bilirubin, direct and indirect: what it means and what to do

Bilirubin is a yellow pigment made when your body recycles old red blood cells. Your liver processes it and clears it in bile. Your report may split it into total, direct and indirect. If it is only slightly high and your other liver tests are normal, Gilbert’s syndrome, which is common and harmless, is often behind it.

Why we test it

Every day your body recycles old red blood cells. The haemoglobin inside them becomes bilirubin, which your liver processes and clears in bile.

If your liver or bile ducts cannot clear it, or if red blood cells break down too fast, bilirubin rises.

It is also the liver value that most often scares people for no reason. When the other tests are normal, the most common cause of a slightly high number is harmless: Gilbert’s syndrome.

What it tells you, and what it does not

If mostly the indirect is high and your other tests are normal, Gilbert’s syndrome is very often behind it. More rarely, red blood cells that break down too early are behind it.

If the direct is high, your liver or bile ducts may not be draining bile well. A doctor needs to look into it.

And on its own it is not enough to say how your liver is doing: the other tests are needed too.

That is why it is read together with other tests:

• Transaminases (ALT and AST): Whether your liver cells are under strain
• GGT: Whether your liver and bile ducts are under strain
• Alkaline phosphatase: Whether bile is flowing well
• Haemoglobin: Whether red blood cells break down too fast

Normal values: total, direct and indirect

The lab decides what is normal. For total bilirubin it is usually 0.2 to 1.2 mg/dL. Your own report may print different limits.

Direct bilirubin (also called conjugated) is the part your liver has already processed, ready to leave in bile. It is usually only a small part of the total, and it has its own limits, printed on your report.

Indirect bilirubin (or unconjugated) is the part your liver has not processed yet. Labs usually do not measure it: they calculate it by taking the direct away from the total.

In the Rosa report you get total bilirubin with your optimal range, and direct and indirect bilirubin as your lab prints them.

What your result means

Find the row for your total bilirubin, in mg/dL. Which values need a doctor? Above 2.3, always. There is no row for direct bilirubin: if your report flags it as high, even with a normal total, talk to a doctor.

• Below your report’s limit, Usually below 0.2: Low. It usually means nothing. You do not need to do anything.
• Within your report’s limits, Usually 0.2 to 1.2: Normal. Usually fine, if your direct bilirubin is within your report’s limits too. In the Rosa report you also see whether you are in your optimal range.
• Above your report’s limit, up to 2.3, The limit is usually 1.2: Slightly high. If everything else is normal, it very often comes from Gilbert’s syndrome, which is harmless, or from fasting before the test. If your direct bilirubin and other liver tests are normal, there is no rush: show your report to your doctor, who can tell you whether it is Gilbert’s syndrome.
• Above 2.3: High. It can still be Gilbert’s syndrome, but at this level other causes need looking for too. Talk to a doctor, and bring your direct bilirubin and other liver tests too.

High bilirubin: indirect or direct?

• High bilirubin: If the total is only slightly high and everything else is normal, Gilbert’s syndrome is very often behind it. Above 2.3, a doctor should see it.
• High indirect bilirubin: It rises with Gilbert’s syndrome, which is harmless, or when red blood cells break down faster than usual.
• High direct bilirubin: It rises when your liver or bile ducts are not draining bile well. A doctor should see it.

What causes high bilirubin

When it is only slightly high and the other tests are normal, the first is the most common.

• Gilbert’s syndrome: A harmless inherited variant: your liver processes bilirubin more slowly, so the indirect stays a little high.
• Fasting, illness, exertion: A long fast, a fever or a hard workout push it up for a while, above all in people with Gilbert’s syndrome.
• Red cells breaking down: If they are destroyed faster than usual, more indirect bilirubin is made. Haemoglobin may then be low.
• A liver under strain: Hepatitis, too much alcohol or some medicines can strain the liver and raise it. The transaminases usually rise too.
• Bile that cannot flow: A stone or a narrowing in the bile ducts holds bile back: the direct rises, often with alkaline phosphatase and GGT.
• Rarer causes: Other inherited forms, or a tumour of the liver, pancreas or bile ducts. That is why a high direct bilirubin always needs a doctor’s look.

Symptoms of high bilirubin

If it is only slightly high, usually none: it is found by chance on a blood test.

When it rises more, jaundice appears: the whites of the eyes, and then the skin, turn yellow. People who already know they have Gilbert’s syndrome sometimes get it for a few days, and it goes away on its own.

If bile is not flowing well, there can also be:

• Dark urine
• Pale stools
• Itching

Gilbert’s syndrome does not usually cause these. With yellow eyes or skin, dark urine or pale stools, see a doctor today. If you also have a fever or bad pain in your belly, call 112 or go to the emergency department. For itching alone, talking to your doctor is enough.

Gilbert’s syndrome

It is a common inherited variant, found in five to eight people in a hundred, more often in men. The liver processes bilirubin more slowly, so the indirect stays a little high.

The number goes up and down. It rises most after fasting, an illness, hard exercise, too little sleep or a stressful stretch. That is why one test can be high and the next one normal.

It does not harm the liver and needs no treatment. Doctors usually think of it when mostly the indirect is high, while transaminases, GGT, alkaline phosphatase and haemoglobin are normal.

What to do if it is high

It depends on which part is high and how you feel. Where to start:

• Check the direct bilirubin and your other liver tests on the report.
• If it is only slightly high and the other tests are normal, there is no rush: show your report to your doctor, who can tell you whether it is Gilbert’s syndrome.
• If your doctor repeats the test, arrive after a few days of regular meals and sleep: the usual overnight fast is enough, do not make it longer.
• If the direct is high, talk to a doctor. With yellow eyes or skin, dark urine or pale stools, see a doctor today. If you also have a fever or bad pain in your belly, call 112 or go to the emergency department.
• Skip liver detox products: they are not needed, and some herbal supplements can even harm the liver.
• With Gilbert’s syndrome you need no special diet: it helps not to skip meals. Before a new medicine, tell your doctor or pharmacist.

What can skew the result

A few things change the number for a while. It helps to know them before you read it.

• A long fast: The blood test is done fasting, but the longer the fast, the more it can rise, above all in men. Have a normal dinner the evening before.
• A recent illness: A fever or an infection in the days before can raise it for a while, especially in people with Gilbert’s syndrome.
• Hard exercise: A tough workout in the days before can raise it for a short while. Arrive at the blood test rested.
• Some medicines: Some push it up. Tell your doctor, and do not stop them without asking.

When to worry

Talk to a doctor if:

• Your total bilirubin is above 2.3.
• Your direct bilirubin is high, even with a normal total.
• It is high together with the transaminases, GGT or alkaline phosphatase.
• It is high and your haemoglobin or albumin is low.
• It stays high when the test is repeated and you do not know why.
• Your eyes or skin are yellow, or you have dark urine or pale stools: see a doctor today. If you also have a fever or bad pain in your belly, call 112 or go to the emergency department.

With Rosa, a total bilirubin above 2.3 is always flagged to a doctor.

Frequently asked questions

Slightly high bilirubin: should I worry? Usually not, if your direct bilirubin, transaminases, GGT, alkaline phosphatase and haemoglobin are normal. Gilbert’s syndrome or fasting is often behind it. Show your report to your doctor, with no rush: they can tell you whether it is Gilbert’s syndrome.

Can stress raise bilirubin? Yes, especially in people with Gilbert’s syndrome. Stress, too little sleep, fasting and illness push it up for a few days, then it comes back down. With Gilbert’s syndrome, these ups and downs do not harm the liver.

Slightly high direct bilirubin: what does it mean? Direct bilirubin rises when your liver or bile ducts are not draining bile well. If you feel well it is not an emergency, but it needs looking into. Your doctor reads it with your other liver tests and decides whether to repeat it or do an ultrasound scan.

Is high bilirubin serious? Usually not: when it is only slightly high and your other liver tests are normal, Gilbert’s syndrome, which is harmless, is very often behind it. A high direct bilirubin, though, always needs a doctor, and with yellow eyes or dark urine, see a doctor today.

Is low bilirubin a problem? Usually not. A low bilirubin does not point to a disease, and you do not need to do anything.

What about high bilirubin in newborns? That is a different topic. In the first days of life many babies turn a little yellow, and it is often normal. But a yellow baby should always be seen by a paediatrician without waiting: this page is about adults.

Sources

• Newsome and colleagues, guidelines on the management of abnormal liver blood tests. Gut, 2018. PMID 29122851
• Fargo and colleagues, evaluation of jaundice in adults. American Family Physician, 2017. PMID 28145671
• De Silva and colleagues, Gilbert’s syndrome: the good, the bad and the ugly. World Journal of Hepatology, 2025. PMID 40027563
• Griffin and colleagues, fasting raises serum bilirubin in healthy men but not in women. Journal of Clinical Pathology, 2014. PMID 24596139
• NHS, patient information on Gilbert’s syndrome, reviewed in August 2025. nhs.uk