This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Skin
Test not used for diagnosis of syphilis 
Select and explain. 
A. VDRL, B. TPI, C. Reagin Test, D. Frei Test
D: Frei Test
Answer: D: Frei Test 
Explanation: D i.e. Frie - test - Most specific test is TPI > FTA -ABSQ Non treponemal test becomes non reactive after t/t; the Treponemal test often remain reactive & therefore not helpful in determining the infection status of person with past syphilis Q. Response to treatment in early syphilis is seen by sequential VDRL or RPR titerQ as they become negative after treatment. CSFVDRL is highly specific but insensitive test; may be nonreactive in symptomatic progressive neuro syphilis. It's sensitivity is highest in meningovascular syphilis & paresis.