What it measures
Bilirubin is a yellow substance made when old red blood cells are broken down. The liver changes it into a form that can leave the body in bile, called conjugated or direct bilirubin. This test measures that processed form.
Why people test it
- Measured when total bilirubin is raised, to help tell a liver or bile duct cause from other causes.
- Used to look into jaundice, the yellowing of the skin and eyes.
- Helps identify Gilbert's syndrome, where total bilirubin is raised but the conjugated form is not.
Typical range
Ranges vary by lab, method, age and sex, and your report shows the lab's own range. One NHS trust gives under 3.4 µmol/L for conjugated bilirubin. Source: Worcestershire Acute Hospitals NHS Trust: Bilirubin (Conjugated).
Finger-prick or vein?
Finger-prick and vein samples are both offered and usually fine. Bilirubin breaks down in light, so labs keep samples out of direct light.