Bilirubin, Direct

The Bilirubin test measures the level of bilirubin in the blood. Bilirubin is a yellow pigment formed from the breakdown of red blood cells. This test is typically divided into total, direct (conjugated), and indirect (unconjugated) bilirubin. Elevated levels can indicate liver dysfunction, bile duct obstruction, or increased red blood cell breakdown.

1. What Is Bilirubin?

• Bilirubin is produced when hemoglobin in red blood cells breaks down.

• The liver processes bilirubin and excretes it through bile into the intestines.

• There are two main forms:

  - Indirect (unconjugated): Not yet processed by the liver.

  - Direct (conjugated): Processed by the liver and ready for excretion.

2. Why Is the Bilirubin Test Performed?

The test is used to:

• Evaluate liver function and detect liver diseases such as hepatitis or cirrhosis.

• Diagnose the cause of jaundice (yellowing of skin and eyes).

• Assess bile duct obstruction or gallbladder disease.

• Monitor newborns for neonatal jaundice.

3. Bilirubin Reference Ranges

• Total Bilirubin: 0.1 – 1.2 mg/dL

• Direct Bilirubin: 0.0 – 0.3 mg/dL

• Indirect Bilirubin: Calculated by subtracting direct from total bilirubin.

4. How to Interpret Bilirubin Results

🔹 Elevated Total Bilirubin:

• May indicate liver disease, bile duct obstruction, or hemolytic anemia.

🔹 Elevated Direct Bilirubin:

• Suggests liver dysfunction or bile duct blockage (e.g., gallstones, tumors).

🔹 Elevated Indirect Bilirubin:

• Often caused by increased red blood cell breakdown or impaired liver uptake (e.g., Gilbert syndrome, hemolysis).

5. What Can Affect Bilirubin Levels?

• Liver diseases (hepatitis, cirrhosis)

• Gallbladder or bile duct conditions (e.g., gallstones, cholestasis)

• Hemolytic anemia or transfusion reactions

• Genetic conditions (e.g., Gilbert syndrome, Crigler-Najjar syndrome)

• Certain medications or alcohol use

6. How to Prepare for the Test

• Fasting may be required for 4–8 hours before the test (follow your provider’s instructions).

• Avoid alcohol and certain medications that affect liver function prior to testing.

7. When to See a Doctor

🚨 Speak to your healthcare provider if you:

• Develop yellowing of the eyes or skin (jaundice)

• Experience dark urine, pale stools, or right upper abdominal pain

• Have a history of liver or gallbladder disease

🔹 Key Takeaways

✅ Bilirubin is a byproduct of red blood cell breakdown processed by the liver.

✅ The test helps assess liver and bile duct function and diagnose jaundice.

✅ Elevated bilirubin levels may suggest liver disease, bile obstruction, or increased hemolysis.