American Board of Internal Medicine (ABIM) Certification Practice Exam

Which diagnostic test is considered the most sensitive for detecting herpes simplex virus infection?

1. Western blot testing

2. Polymerase chain reaction testing

3. Serum antibody testing

4. Immunoassay

The correct answer is: Polymerase chain reaction testing

Polymerase chain reaction (PCR) testing is recognized as the most sensitive method for detecting herpes simplex virus (HSV) infections. This sensitivity stems from PCR's ability to amplify specific viral DNA sequences, allowing for the detection of even minute quantities of HSV genetic material in samples. This makes it particularly valuable in cases where the lesion may not be actively shedding the virus or may not be readily detectable by other methods. PCR testing is not only sensitive for diagnosing active infections but can also distinguish between HSV-1 and HSV-2, providing a more tailored approach to patient management. Its high sensitivity is essential, especially in situations where clinical presentation is ambiguous or when rapid diagnosis is needed to guide treatment decisions. In contrast, other methods, like serum antibody testing, may miss acute infections or take several weeks to show positive results, as they detect the body's immune response rather than the virus itself. Western blot testing, while highly specific and useful for confirming diagnoses, is generally not as sensitive as PCR for initial detection. Immunoassays can vary in sensitivity and specificity depending on their design and the stage of the infection but typically do not reach the sensitivity levels of PCR for HSV detection. Thus, PCR remains the gold standard in clinical settings for the reliable identification of herpes