Question

The confirmatory test for bile pigments in urine is:

• A. Hay's test
• B. Benedict's test
• C. Fouchet's test
• D. Rothera's test

Hint:

Remember: Fouchet's test is for bile pigments, Hay's test is for bile salts, Benedict's test is for glucose, and Rothera's test is for ketone bodies.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Bile pigments (primarily bilirubin) are breakdown products of hemoglobin. Their presence in urine (bilirubinuria) typically indicates liver disease or bile duct obstruction. Specific biochemical tests are used to detect these pigments.
Step 2: Detailed Explanation:
1. Fouchet’s Test: This is the standard confirmatory test. It involves the use of Fouchet's reagent (which contains trichloroacetic acid and ferric chloride).
2. Reaction: Barium chloride is first added to urine to precipitate the pigments. When Fouchet’s reagent is added to the precipitate, the ferric chloride oxidizes the yellow bilirubin into green biliverdin or blue cholecyanin. A green or blue color indicates a positive result.
3. Others: Hay’s test is for bile salts. Benedict’s test is for reducing sugars (glucose). Rothera’s test is for ketone bodies.
Step 3: Final Answer:
Fouchet’s test is specifically designed to confirm the presence of bile pigments through an oxidation-reduction reaction.