The antigen used in the Venereal Disease Research Laboratory (VDRL) test is composed of:
- A Cardiolipin, cholesterol and dextrose
- B Cardiolipin, lecithin and cholesterol ✓
- C Reiter treponemal protein, cardiolipin and lecithin
- D Nichols strain sonicate, lecithin and charcoal
Correct answer: B. Cardiolipin, lecithin and cholesterol
Explanation
The VDRL is a non-treponemal flocculation test using a buffered saline suspension of cardiolipin, lecithin and cholesterol. Cardiolipin provides the antigenic determinant cross-reacting with reagin antibody, lecithin enhances sensitivity and cholesterol stabilises the antigen complex. The Reiter treponeme is used as the sorbent in FTA-ABS to absorb cross-reactive group antibodies, not as VDRL antigen. Charcoal is added to the same antigens in the RPR to make flocculation visible macroscopically.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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