Question

Coomb's test is used for detection of:

• A. Yellow fever
• B. Syphilis
• C. Typhoid
• D. Antiglobulin

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The Coomb's test is a specific immunological test, and its own name, the antiglobulin test, is a direct clue to what it is used to detect.

Step 2: Key Concept or Approach:
Compare the Coomb's test's actual purpose, detecting antibodies coating red blood cells using anti-human globulin reagent, against the diseases listed in the options.

Step 3: Detailed Explanation:
Yellow fever, syphilis and typhoid are each diagnosed using their own dedicated tests, viral serology or PCR for yellow fever, VDRL or treponemal tests for syphilis, and the Widal test or culture for typhoid. None of these use the Coomb's test.
The Coomb's test itself works by adding anti-human globulin reagent to a blood sample; if antibodies or complement are bound to the red cells, the reagent causes them to clump together, giving a positive result.
This mechanism is why the test is also simply called the antiglobulin test, direct or indirect depending on whether the antibodies are already on the cells or free in the serum.

Step 4: Final Answer:
The Coomb's test is used for detection of antiglobulin, meaning antibodies bound to red blood cells.