Bilirubin – Part of your Liver Function Testing: a routine biomarker

The Biomarker Handbook is a curated series that seeks to provide readers with insights on each biomarker we cover in our blood test packages and its relation to our body.


The liver is one of the body’s vital organs – primary producer of bile to aid digestion of fats, and one of our body’s detoxifying powerhouse. Bilirubin testing is part of a routine lab test called liver function testing, or LFT. It is generally used to screen for, detect, evaluate, and monitor acute and chronic liver inflammation (hepatitis), liver infection, liver disease and/or damage. Amongst the many liver biomarkers tested, the levels of bilirubin in the body can give a good indication of several conditions.

The American Association for Clinical Chemistry (AACC) reports that around half of all newborns have jaundice for the first few days of their lives; however, for most it fades as bilirubin levels stabilise within a few days of birth.

Bilirubin: What is it?

When red blood cells (RBC) reach their age limit (normally averaging 120 days), they are broken down by the body to their constituents. One such constituent is heme, which is further broken down into a yellowish compound called bilirubin. The liver then processes bilirubin to allow its elimination from the body. This multistep enzymatic process is important to rid the body of heme which can be harmful for the cells.

Bilirubin levels give a good evaluation of our liver function, and help diagnose anaemias caused by RBC destruction (haemolytic anaemia).

Bilirubin forms a major part of bile which is stored in the gall bladder and released in the intestines.

Types of Bilirubin

Bilirubin can be of two forms – indirect (unconjugated) or direct (conjugated). The sum of these two forms is called the total bilirubin in the blood.

Indirect bilirubin is produced directly after the breakdown of heme. It does not undergo any chemical process, and is carried to the liver in the blood combined with the protein albumin in its original, insoluble form.

Direct bilirubin, on the other hand, is when the indirect bilirubin undergoes a chemical conjugation with glucuronic acid to form a soluble version of bile.

The total bilirubin level in adults is normally up to 1.2 mg/dL. This value is slightly lower in children. The normal level of direct bilirubin is about 0.3 mg/dL; the rest is indirect.

Importance of the Bilirubin Test

Testing for the levels of bilirubin in the blood can be of a diagnostic value in a number of diseases.

Indirect bilirubin can result from increased production, impaired conjugation, or impaired hepatic uptake of bilirubin. It can be the result of Gilbert syndrome (5% of the population suffers from this and may not know it), Crigler-Najjar syndrome which is diagnosed during childbirth, and neonatal jaundice.

Direct bilirubin levels may be elevated from three causes:

  1. From within the liver: exposure to liver toxins, alcoholism, certain hepatitis (cytomegalovirus), acute fatty liver of pregnancy, inherited condition (rotor syndrome)
  2. From biliary obstruction: A blockade in the gallbladder by gallstones, inflammation or carcinoma of the gallbladder
  3. From outside the liver: drug toxicity (such as pacacetamol and non-steroidal anti-inflammatories); pancreatitis; chemotherapy causing occlusion of certain large vessels; Reye’s syndrome.

Signs and Symptoms of Abnormal Bilirubin Levels

A rise in bilirubin levels above the normal range can show classic signs such as:

  • Jaundice, yellowing of the skin and sclera (the white part of your eyes)
  • Dark colored urine
  • Clay colored stools
  • Nausea
  • Abdominal pain or swelling
  • Vomiting
  • Weakness and fatigue
  • Itching, mood change, insomnia

As seen before, there are many possible causes for an elevation of your bilirubin, and each of these may come with their specific signs and symptoms. It is important that anyone with jaundice seek medical advice for an appropriate workup, even if symptoms are mild.

Balancing Bilirubin Levels with Diet

A mild to moderate rise in bilirubin levels in the plasma can be rectified by consuming a healthy diet. Whether you have a healthy liver or not, it is recommended that a liver-healthy diet be followed considering the importance of this organ.

Foods that promote liver function include whole grains, fish, vegetables and olive oil. Fibre is also helpful in maintaining good liver health. Vegetables and fruits rich in fibre should be included in the diet of a patient with hyperbilirubinemia.

Tomatoes, radishes and barley are other food items that improve liver function. Tomatoes are rich sources of lycopene and antioxidant. Lycopene helps to lower bilirubin levels. Other lycopene rich sources include guavas and watermelons. Similarly, barley and radishes help to flush out harmful toxins from the liver which can reduce bilirubin levels in the plasma.

It is also recommended to cut off unhealthy foods from the diet: sugar, sodas and processed food. These can cause the liver to become fatty and bilirubin levels to rise.

Medically Approved Ways to Treat Hyperbilirubinemia

Hyperbilirubenemia is not considered an actual disease but a consequence of an underlying pathology. In order to treat increased levels of bilirubin and its associated symptoms, it is important to investigate and diagnose the underlying condition causing the rise in the level of this biomarker.

It is important to check in with the doctor and get the disease managed and treated with proper intervention. Gilbert’s syndrome, for example, is treated with reassurance that the condition is benign and not fatal to the patient, together with the above-mentioned liver-friendly diet. Other diseases that cause hyperbilirubinemia like cirrhosis, anemia and drug reactions will need their own specific treatment options.

When to See a Doctor

If the symptoms of high bilirubin levels are present, professional advice from the doctor is recommended. Although the symptoms may start off mild, they might progress if left unchecked. Therefore it is important to recognize the signs of hyperbilirubinemia and get it treated as soon as possible.

Tests for Bilirubin Levels

The basic tests to measure bilirubin levels in our system include a urine and blood test. Urine test is usually the first test performed after which complete liver functions test may be taken.

Bilirubin levels are also assessed by other tests that include a general physical exam where the doctor can palpate and check if the liver is enlarged and/or tender. A complete blood count can also help in detecting any abnormality in haemoglobin levels and their appearance (morphology). If a liver infection is suspected, your doctor may start ordering hepatitis B, A and/or C screening. Ultrasounds, CT scans and MRIs may also be performed to rule out any damage to the liver. With the arrival of highly sensitive and specific liver blood tests that can detect fatty liver, fibrosis or inflammation of the liver (replacing fibroscans, other forms of imaging and even a liver biopsy- except for cancer) see your doctor and ask for these novel testings called liverfast.

Testing for bilirubin levels in the blood becomes a necessity whenever the signs are suspected. Jaundice is usually one of the first signs that is apparent, and points to an underlying disease of the liver-bile system. Although the symptoms of increased levels of bilirubin are not life-threatening, the disease causing these abnormal levels might be. Hence it is necessary to identify and treat the disease as soon as possible.


If you want to find out more about bilirubin diseases and how you can balance bliirubin levels, take a look at our lifestyle article here!

Interested in other biomarkers? Check out the rest of The Biomarker Handbook.

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