American Board of Internal Medicine (ABIM) Certification Practice Exam

Which statement best summarizes the result consistency of nonspecific syphilis tests in the context of disease progression?

1. Always positive regardless of stage

2. Generally negative in primary but positive in secondary

3. Positive in latent but negative in secondary

4. Equal positivity in all stages

The correct answer is: Generally negative in primary but positive in secondary

The statement that nonspecific syphilis tests are generally negative in the primary stage but positive in the secondary stage accurately reflects the serologic response to syphilis as the disease progresses. In primary syphilis, which is characterized by the presence of a chancre and localized lymphadenopathy, the body has not yet mounted a significant immune response, and therefore, these nonspecific tests typically yield negative results. As the disease progresses into secondary syphilis, characterized by systemic dissemination of the Treponema pallidum organism, the immune response becomes more robust. Nonspecific tests, such as the Rapid Plasma Reagin (RPR) or Venereal Disease Research Laboratory (VDRL) tests, detect antibodies that increase in response to the infectious process. Consequently, most patients will test positive during this secondary stage. Understanding this progression is crucial as it highlights the need for clinicians to interpret nonspecific syphilis tests in the context of the clinical stage of the disease, and to be aware that initial testing in primary syphilis may not reflect the presence of disease accurately until the later stages.