All are true about FTA-ABS in Syphilis, except –
**Core Concept**
FTA-ABS (Fluorescent Treponemal Antibody Absorption) test is a treponemal test used for the serological diagnosis of syphilis, detecting antibodies against Treponema pallidum. It is a specific and sensitive test, but it remains positive for life, even after successful treatment.
**Why the Correct Answer is Right**
FTA-ABS test detects the presence of specific antibodies against Treponema pallidum, indicating a current or past infection. The test is highly specific, but it has a low sensitivity in the early stages of syphilis. This is because the body takes time to produce antibodies against the treponeme, and the test may be negative in primary syphilis.
**Why Each Wrong Option is Incorrect**
**Option A:** FTA-ABS test is not the first line of screening for syphilis. The Venereal Disease Research Laboratory (VDRL) test or the Rapid Plasma Reagin (RPR) test is used as the initial screening test.
**Option B:** FTA-ABS test is not a false-positive test. It is highly specific, and false-positive results are rare.
**Option C:** FTA-ABS test is not a test for other diseases. It is specific to Treponema pallidum and is used for the diagnosis of syphilis.
**Clinical Pearl / High-Yield Fact**
It's essential to note that treponemal tests like FTA-ABS are used in conjunction with non-treponemal tests like VDRL or RPR to diagnose syphilis. A positive treponemal test indicates a current or past infection, but a negative non-treponemal test may indicate early syphilis or a false-negative result.
**Correct Answer: A.**