Serum or plasma concentration of total bilirubin

Why This Test Matters

Bilirubin is a byproduct of hemoglobin breakdown, which occurs naturally in your body. When your liver struggles to process it properly, bilirubin builds up and can cause yellowing of the skin or eyes (jaundice). This test helps doctors identify whether your liver, gallbladder, or bile ducts are functioning correctly or if there’s another issue affecting red blood cell breakdown.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw from a vein in your arm, or if plasma is collected, it might be drawn into a special tube. If you’re on a blood thinner, let your doctor know before the test.

What the Results Mean

Higher-than-normal bilirubin levels may indicate liver disease, infections, hemolytic anemia (where red blood cells break down too quickly), or blockages in the bile ducts. Lower-than-normal levels are less common but could suggest certain genetic conditions or liver damage.

Common Conditions Linked to Bilirubin Levels

Elevated bilirubin is often seen in conditions like hepatitis (liver inflammation), cirrhosis, gallstones, or severe anemia. Doctors may also check bilirubin if you have unexplained jaundice, dark urine, or pale stools.