Bilirubin Direct

Bilirubin Direct Test (Conjugated Bilirubin)

The Widal test is a blood test used to detect typhoid and paratyphoid fever, which are caused by Salmonella bacteria. It measures the presence of specific antibodies (agglutinins) against Salmonella typhi (O and H antigens) and Salmonella paratyphi (AH and BH antigens) in the patient’s blood.

Why it's done

To evaluate liver function
To help diagnose liver diseases (e.g., hepatitis, cirrhosis)
To detect blockages in the bile ducts (e.g., gallstones, tumors)
To investigate the cause of jaundice

Preparation

Sample Required:
A blood sample

Fasting Required:

Fasting for 8–12 hours is often recommended for more accurate results.

Result

Unit	Normal Range
mg/dL	0.1 – 0.3 mg/dL
µmol/L	1.7 – 5.1 µmol/L

Interpretation

Elevated Direct Bilirubin may indicate:
- Liver diseases (e.g., hepatitis, alcoholic liver disease)
- Bile duct obstruction (e.g., gallstones, tumors)
- Drug-induced liver injury
Normal Direct Bilirubin with high total bilirubin may suggest elevated indirect bilirubin instead (e.g., in hemolytic anemia or Gilbert’s syndrome)