Summary

Total bilirubin, a blood biomarker, measures bilirubin levels, reflecting liver function and bile duct health. Abnormally high levels may indicate conditions like hepatitis, cirrhosis, or hemolytic anemia, while low levels are typically less concerning but can occur due to certain medications.

‍

Overview

Total bilirubin represents the aggregate amount of direct and indirect bilirubin in the body, products of red blood cell catabolism (breaking down complex molecules into simpler ones.). 

Bilirubin is a yellowish substance made during your body's normal process of breaking down old red blood cells. It is found in bile, a fluid your liver makes that helps you digest food.

High bilirubin levels, or hyperbilirubinemia, can suggest liver or gallbladder disease, blockage of the bile ducts, or accelerated breakdown of red blood cells. Symptoms can include jaundice (yellowing of the skin), dark urine, or light-colored stools. Conversely, low bilirubin levels, though not usually a cause for concern, might occur due to the effect of certain drugs. The total bilirubin test is an important part of the liver panel, offering insight into liver function and potential disease states.^[1,2] 

Bilirubin monitoring is also essential in newborns, as elevated levels can lead to hyperbilirubinemia, resulting in jaundice.^[7] Newborn jaundice is usually not harmful and clears up within a few weeks. But in some cases, high bilirubin levels can lead to more serious problems, so infants are often tested as a precaution.

‍

What should you know about this biomarker?

Each laboratory uses different machines and protocols, so the results might vary in terms of the reference ranges or used units of measurement. In Macromo blood tests, we use µmol/l (micromol per liter), but you can also find the levels expressed in mg/dl (milligrams per deciliter).

Normal total bilirubin levels range from 3-21 µmol/l. Lower bilirubin levels are typically not considered a problematic situation. They can be caused by strenuous exercise or drugs like barbiturates, penicillin, NSAIDs (nonsteroidal anti-inflammatory drugs), or caffeine. Bilirubin levels may vary depending on factors such as age, sex, and individual characteristics.^[3] In clinical practice, total bilirubin test results are evaluated with other liver markers such as ALT, AST, or ALP.

There are three possible states of your blood test result: low, average, and high levels.

• The level of total bilirubin is under the reference range. This is usually not something to be concerned about, but consult your doctor if you notice anything unusual.
• The level of total bilirubin is within the standard range, which is a sign of good health. 
• The level of total bilirubin is above the standard range, which may indicate potential liver, gall bladder or blood problems. 

‍

Genetics

Our genetic makeup can play a role in dictating our total bilirubin levels. Two genetically inherited conditions, namely Gilbert's syndrome and Crigler-Najjar syndrome, are examples of how genetic variations can impact bilirubin metabolism, leading to varying bilirubin concentrations in the bloodstream. 

Gilbert's syndrome, a common and benign condition, stems from a minor genetic change that affects the liver's ability to process bilirubin efficiently. This leads to elevated bilirubin levels. However, most individuals with Gilbert's syndrome remain asymptomatic or experience only mild jaundice.^[4] 

On the end of the spectrum, there is Crigler-Najjar syndrome. It is a rare and more severe genetic disorder that occurs when the body lacks the necessary enzyme to transform bilirubin into an easily excreted form. The resulting high bilirubin levels lead to pronounced jaundice and can trigger severe health complications.^[5]

Therefore, our genes can influence the total bilirubin concentrations within our bodies.^[6]

‍

Recommendations

When total bilirubin levels fall outside the normal range, it's essential to consider the following recommendations:

• An abnormal total bilirubin level should be confirmed with repeated testing to rule out any lab errors.
• Elevated bilirubin levels can indicate several conditions, such as liver diseases, bile duct blockage, or excessive hemolysis. Though less common, low levels may arise from certain conditions or medication effects. Physicians may recommend additional tests to pinpoint the cause.
• If an inherited condition like Gilbert's syndrome or Crigler-Najjar syndrome is suspected, genetic testing might be suggested.
• If liver disease is present or suspected, reducing alcohol intake can help protect the liver.
• Eating a balanced diet and maintaining a healthy weight supports overall liver health.
• Engaging in regular physical activity can contribute to maintaining a healthy weight and liver function.
• Evaluate current medications and supplements, as some can influence bilirubin levels.

‍

The information and tests provided on our website are for educational purposes only and are not a substitute for professional medical advice. Always consult with your healthcare provider before making health decisions. Our tests do not diagnose or treat diseases. Individual results may vary and should be discussed with a healthcare provider.