Need Help?
+91 94294 10291
.png)
The Serum Bilirubin Blood Test is a common laboratory test used to assess bilirubin levels in the blood and help evaluate liver function, bile flow and the breakdown of red blood cells. Bilirubin is a yellowish pigment produced naturally when the body breaks down old red blood cells. The liver processes bilirubin and helps remove it from the body through bile.
When bilirubin levels become elevated, it may cause jaundice, which is characterised by yellowing of the skin and the whites of the eyes. An abnormal result can have several possible causes, so understanding the test and its results is important for maintaining overall health.
In this guide, we explain what the serum bilirubin test measures, its normal range, the causes of high bilirubin levels, test preparation and when this test may be recommended.
A serum bilirubin test measures the amount of bilirubin present in the liquid part of the blood, known as serum. It helps healthcare professionals evaluate how the body processes bilirubin and whether there may be an issue involving the liver, bile ducts or red blood cells.
Bilirubin forms when old red blood cells are broken down. It travels through the bloodstream to the liver, where it is processed and eventually eliminated through bile.
If the liver cannot process bilirubin properly or bile flow becomes obstructed, bilirubin may accumulate in the blood. This can result in elevated bilirubin levels and sometimes jaundice.
The test may be performed individually or as part of a broader liver function test profile.
A healthcare professional may recommend a serum bilirubin blood test for several reasons.
1. To evaluate liver health
Bilirubin levels can provide useful information when assessing possible liver conditions, including hepatitis and other disorders that affect liver function.
2. To investigate jaundice
Yellowing of the skin or eyes may indicate increased bilirubin levels. Testing helps identify the extent of the elevation and guides further evaluation.
3. To investigate bile duct problems
Conditions such as gallstones or bile duct obstruction can interfere with the normal flow of bile and cause bilirubin levels to rise.
4. To assess red blood cell breakdown
When red blood cells break down faster than usual, bilirubin production can increase. This may occur in certain blood disorders.
5. To monitor an existing condition
The test may be repeated to monitor bilirubin levels over time or assess changes during treatment.
A bilirubin test may include total bilirubin, direct bilirubin and indirect bilirubin. Each measurement provides different information about how bilirubin is processed in the body.
Total bilirubin represents the overall amount of bilirubin in the blood. It includes direct and indirect bilirubin.
This measurement helps identify whether bilirubin levels are elevated and whether further investigation may be required.
Direct bilirubin is also called conjugated bilirubin. It refers to bilirubin that has been processed by the liver and made water-soluble so that it can be excreted through bile.
Elevated direct bilirubin may be associated with liver conditions or problems affecting bile flow.
Indirect bilirubin is also called unconjugated bilirubin. It is the form produced before the liver processes bilirubin.
Higher indirect bilirubin may occur when red blood cells break down more rapidly than usual or when the liver has difficulty processing bilirubin. Certain inherited conditions can also cause mild elevations.
Indirect bilirubin is commonly calculated by subtracting direct bilirubin from total bilirubin.
The normal bilirubin range may vary depending on the laboratory, testing method, age and individual health factors. The reference interval printed on your laboratory report should be used when interpreting your results.
The following values are commonly used as general adult reference examples.
| Bilirubin Type | General Adult Reference Range |
|---|---|
| Total Bilirubin | Approximately 0.1–1.2 mg/dL |
| Direct Bilirubin | Usually less than 0.3 mg/dL |
| Indirect Bilirubin | Often approximately 0.2–0.9 mg/dL |
Note: These are general adult reference examples. Normal ranges vary by laboratory, testing method and individual factors. Newborns require age-specific interpretation. Always refer to the reference range printed on your laboratory report.
These values are illustrative rather than universal. Some laboratories use different reference intervals, and the ranges for newborns differ significantly from those for adults.
A result outside the reference range does not automatically confirm a particular disease. A healthcare professional considers the bilirubin level alongside symptoms, medical history and other test results.
A high bilirubin level is known as hyperbilirubinemia. It indicates that bilirubin is accumulating in the blood and may require further evaluation to identify the cause.
Possible causes include:
Liver conditions: Hepatitis, cirrhosis and other liver disorders can affect the processing or removal of bilirubin.
Bile duct obstruction: Gallstones or other conditions that obstruct bile flow may increase bilirubin levels.
Increased red blood cell breakdown: Certain types of haemolytic anaemia and other blood disorders can cause bilirubin production to increase.
Inherited conditions: Conditions such as Gilbert syndrome can cause mild increases in indirect bilirubin.
Certain medicines or other factors: Some medications and health circumstances may affect bilirubin levels. Their significance depends on the individual situation.
High bilirubin should be interpreted according to the pattern of direct and indirect bilirubin levels and other clinical findings. The number alone cannot determine the underlying cause.
Elevated bilirubin may occur with or without noticeable symptoms. When symptoms are present, they can include:
These symptoms can occur for different reasons and do not establish a diagnosis on their own. New yellowing of the eyes or skin should be assessed promptly by a healthcare professional. Severe abdominal pain, fever, confusion or rapidly worsening symptoms require urgent medical attention.
Low bilirubin levels are generally not considered a significant concern. In most cases, a result below the laboratory's reference interval does not indicate a serious health problem.
Certain medicines and other individual factors may influence bilirubin measurements. If a result is unexpectedly low or appears alongside other abnormal findings, a healthcare professional can determine whether any follow-up is needed.
The serum bilirubin test is a routine blood test performed in a laboratory.
The process generally involves the following steps:
Blood collection usually takes only a few minutes. Some people may experience mild discomfort or temporary bruising at the collection site.
Fasting requirements depend on the laboratory's instructions and whether the bilirubin test is being performed alongside other blood tests.
A standalone bilirubin test may not always require fasting. However, a healthcare professional may recommend avoiding food or drink for a specified period before testing, particularly when other investigations are included.
Before your test:
Following the correct preparation instructions helps ensure that the test is performed appropriately.
A serum bilirubin test focuses specifically on bilirubin levels, while a liver function test profile generally includes several laboratory measurements used to evaluate different aspects of liver health.
| Feature | Serum Bilirubin Test | Liver Function Test Profile |
|---|---|---|
| Main Purpose | Measures bilirubin levels in the blood. | Assesses multiple markers related to liver health. |
| Common Measurements | Total bilirubin and, when ordered, direct and indirect bilirubin. | May include bilirubin, ALT, AST, ALP and other markers. |
| Helps Investigate | Jaundice and abnormalities in bilirubin levels. | Possible liver injury, bile flow problems and other liver-related conditions. |
| Scope | A focused assessment of bilirubin. | A broader assessment using several laboratory measurements. |
Note: The tests included in a liver function profile vary by laboratory. Your healthcare professional can recommend the appropriate tests based on your symptoms and medical history.
The exact tests included in a liver function profile vary by laboratory. A bilirubin result is only one part of the overall assessment, and additional tests may be required depending on the clinical situation.
A healthcare professional may recommend a serum bilirubin test for people who:
The test may also be recommended for newborns when evaluating jaundice. Bilirubin levels in newborns must be interpreted according to the baby's age in hours, gestational age and other clinical factors.
Healthy daily habits can contribute to overall well-being and help reduce some risk factors associated with liver disease.
Maintain a balanced diet: Include a variety of vegetables, fruits, whole grains and appropriate protein sources.
Stay physically active: Regular physical activity supports general health and can help maintain a healthy weight.
Limit alcohol consumption: Alcohol can contribute to liver damage. Avoiding alcohol is particularly important for people with existing liver disease.
Use medicines responsibly: Follow medical advice regarding prescription medicines, over-the-counter products and supplements. Some substances can affect the liver.
Take preventive measures: Follow recommended vaccination advice, practise safe hygiene and avoid sharing needles or personal items contaminated with blood.
Attend recommended health check-ups: Appropriate laboratory testing can help identify abnormalities that may require further evaluation.
These habits support general health but do not replace medical assessment when bilirubin levels are elevated or symptoms are present.
At VIP LABS, laboratory testing helps individuals and healthcare professionals obtain information that supports health assessment and clinical decision-making.
If you have been advised to undergo a serum bilirubin test or a broader liver function assessment, you can explore the available testing options and seek guidance on the appropriate test for your needs.
You can visit the VIP LABS website to learn more about laboratory services. You can also explore the test and parameter directory or review the available health check-up packages.
For convenient access to testing services, visit the VIP LABS online lab test booking page.
Choosing the appropriate test depends on your symptoms, medical history and healthcare professional's recommendations.
1. What is the serum bilirubin blood test used for?
The serum bilirubin blood test measures bilirubin levels in the blood. It helps evaluate jaundice and may support the investigation of liver conditions, bile duct obstruction or increased red blood cell breakdown.
2. What is the normal serum bilirubin range for adults?
A commonly used adult reference range for total bilirubin is approximately 0.1–1.2 mg/dL. Direct bilirubin is often below 0.3 mg/dL. Exact ranges vary between laboratories, so check the reference interval on your report.
3. What causes high bilirubin levels?
High bilirubin may result from liver disease, bile duct obstruction, increased red blood cell breakdown or inherited conditions such as Gilbert syndrome. Further assessment may be needed to identify the cause.
4. Is fasting necessary before a bilirubin blood test?
Fasting is not always necessary for a standalone bilirubin test. Requirements may differ when other tests are performed at the same time. Follow the instructions provided by your laboratory or healthcare professional.
5. Does high bilirubin always mean liver disease?
No. High bilirubin does not always indicate liver disease. It can also occur because of increased red blood cell breakdown or certain inherited conditions. Direct and indirect bilirubin levels, symptoms and other test results help guide interpretation.
6. Which other tests may be recommended with a bilirubin test?
Depending on the clinical situation, a healthcare professional may recommend ALT, AST, alkaline phosphatase, a complete blood count or other investigations. These tests can help assess possible causes of an abnormal bilirubin result.
The serum bilirubin blood test is an important laboratory investigation that helps assess bilirubin levels and supports the evaluation of liver health, bile flow and red blood cell breakdown. Understanding total, direct and indirect bilirubin can help explain what the results may indicate.
Although high bilirubin levels can be associated with jaundice and several underlying conditions, the result must be interpreted in context. Reference ranges vary between laboratories, and additional tests may be needed to identify the cause of an abnormal result.
If you notice yellowing of the skin or eyes, dark urine or other concerning symptoms, seek medical evaluation. For information about available laboratory tests and health check-up services, visit VIP LABS and explore the testing options relevant to your needs.