American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the mainstay method for diagnosing syphilis?

1. Serologic testing

2. Direct observation

3. Imaging studies

4. Cultures

The correct answer is: Serologic testing

The primary method for diagnosing syphilis is serologic testing. This approach is effective because it detects antibodies produced in response to the Treponema pallidum bacterium, which causes syphilis. There are two main types of serologic tests: non-treponemal tests (like the RPR and VDRL) and treponemal tests (like the FTA-ABS). Non-treponemal tests are typically used for initial screening, while treponemal tests confirm a positive result from a non-treponemal test. Serologic testing is preferred due to its ability to assess the presence of syphilis across different stages of the disease, including primary, secondary, and latent syphilis. It is also relatively quick, efficient, and can be performed on blood samples. The tests are widely available and validated for use in clinical settings, making them the cornerstone of syphilis diagnosis. Other methods such as direct observation or imaging studies are not commonly utilized for syphilis diagnosis. Direct observation focuses on identifying the physical manifestations of the disease, such as chancres, which may not be present early on. Imaging studies may help assess complications of syphilis but do not specifically diagnose the