Dangerous bilirubin levels in adults

Bilirubin is a yellowish pigment formed when old red blood cells are broken down by the liver. Measuring bilirubin in the blood helps assess how well your liver and bile ducts are working. In adults, a persistently high level of bilirubin can point to conditions ranging from mild inherited variations to serious issues like acute liver failure or bile duct obstruction. Knowing which levels are normal, when to be concerned and what to do next can help you and your healthcare team address any problems early and effectively.

What is bilirubin
Bilirubin exists in two forms: unconjugated (indirect) and conjugated (direct). Unconjugated bilirubin circulates bound to a protein called albumin and is taken to the liver for processing. In the liver it is converted into conjugated bilirubin, which is water‑soluble and excreted in bile. Most UK laboratories report total bilirubin, with a normal adult range up to about 21 micromoles per litre. Direct bilirubin normally falls below around 8 micromoles per litre. Levels outside these ranges warrant further investigation.

Signs and symptoms of elevated bilirubin
A rise in bilirubin typically presents as jaundice—a yellowing of the skin and the whites of the eyes—often noticeable once total bilirubin exceeds around 35 micromoles per litre. You may also see dark urine and pale stools as bilirubin is diverted away from the intestines. When levels climb above about 150 micromoles per litre, intense itching (often called “bile itch”) can occur due to bilirubin stimulating skin itch receptors.

Causes or contributing factors
Elevated bilirubin can arise before, within or after the liver. Pre‑hepatic causes involve excessive breakdown of red blood cells (haemolytic anaemias). Hepatic causes relate to impaired processing within the liver itself—examples include viral hepatitis, alcoholic liver disease or inherited conditions such as Gilbert’s syndrome. Post‑hepatic causes occur when bile cannot flow out of the liver, for instance due to gallstones or strictures in the bile ducts. In each case, bilirubin clearance is disrupted, leading to its build‑up in the bloodstream.

Diagnosis and testing
If your blood test shows raised bilirubin, your doctor will usually order additional liver function tests to check related enzymes and proteins. The report will often distinguish between direct and indirect bilirubin. Imaging such as ultrasound, MRI or CT scans may follow to visualise the liver and bile ducts. Occasionally, a liver biopsy is needed to confirm the diagnosis. Only by combining blood results with clinical examination and imaging can the underlying cause be clearly identified.

What constitutes a dangerous level
There is no single cut‑off for everyone, but general thresholds guide action. Total bilirubin above 35 micromoles per litre usually indicates clinical jaundice and calls for investigation. Levels above 50 micromoles per litre often suggest significant liver or bile duct dysfunction. Readings over 100 micromoles per litre typically point to severe obstruction or acute liver failure. In critical care settings, even levels above around 34 micromoles per litre (equivalent to 2 mg/dL) have been linked with higher risk, highlighting the need for prompt assessment when high values appear.

Treatment and management
Treatment depends on the underlying cause of the bilirubin rise. In haemolysis, addressing the blood disorder can restore balance. Viral hepatitis or other liver injuries may be treated with antiviral or anti‑inflammatory therapies alongside supportive care. Obstruction from gallstones often requires endoscopic or surgical removal of the blockage. In mild inherited hyperbilirubinaemia, treatment is seldom needed unless symptoms such as itching become severe—then medications that bind bile salts can provide relief.

Prevention and lifestyle tips
While some causes of raised bilirubin lie beyond personal control, you can protect your liver through healthy habits. Limit alcohol intake, maintain a balanced diet and exercise regularly to support liver function. Avoid unregulated herbal supplements, which can sometimes harm the liver. Vaccinations against hepatitis A and B are recommended for those at risk. If you have a family history of gallstones or inherited liver conditions, discuss screening options with your GP for earlier detection.

When to seek help
Seek medical advice promptly if you notice any jaundice—especially if it comes with abdominal pain, fever or confusion. Likewise, if you already have a known liver condition or gallstones and your bilirubin level rises or symptoms worsen, contact your specialist team without delay. Early intervention can prevent complications such as acute liver failure or bile duct infection.

Common myths and misconceptions
Not every rise in bilirubin is an emergency. Mild elevations below around 30 micromoles per litre often occur in harmless inherited syndromes and require only reassurance. Conversely, a normal bilirubin level does not rule out liver disease, since some conditions show normal bilirubin until later stages. Understanding that bilirubin is only one piece of the diagnostic puzzle helps avoid unnecessary alarm or false reassurance.

Emotional and mental health impact
Abnormal liver tests can trigger anxiety, sleepless nights and fears about serious illness. Uncertainty about lifestyle changes or the seriousness of your results can add stress. Sharing your concerns with a GP, specialist nurse or counsellor can help you process these emotions. Joining support groups for people with liver conditions often brings both comfort and practical advice, reducing feelings of isolation.

Summary
Bilirubin is a key marker of liver and bile duct health. In adults, total levels above 35 micromoles per litre usually signal jaundice and require investigation. Levels above 50 suggest significant dysfunction, while readings over 100 indicate severe disease. Early diagnosis through blood tests and imaging guides treatment tailored to the cause—whether managing haemolysis, clearing an obstruction or supporting liver recovery. By adopting liver‑friendly habits and seeking help promptly if symptoms arise, you can protect your health and address any bilirubin elevation effectively.