American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the main benefit of the galactomannan antigen immunoassay in diagnosing invasive aspergillosis?

1. It can confirm a diagnosis through culture

2. It has high sensitivity and specificity for high-risk patients

3. It detects all fungal infections

4. It is easier to perform than a biopsy

The correct answer is: It has high sensitivity and specificity for high-risk patients

The primary benefit of the galactomannan antigen immunoassay in diagnosing invasive aspergillosis lies in its high sensitivity and specificity in high-risk patient populations. This test detects the presence of galactomannan, a component of the Aspergillus cell wall, in the bloodstream. The test is particularly valuable for patients who are immunocompromised, such as those undergoing chemotherapy, organ transplantation, or suffering from hematologic malignancies, who are at increased risk for invasive aspergillosis. The high sensitivity means that a negative result can effectively rule out the disease in these populations, while its high specificity indicates that a positive result strongly suggests the presence of invasive aspergillosis, thereby aiding in timely diagnosis and treatment. Quick and accurate identification of the condition is critical, as invasive aspergillosis can progress rapidly in high-risk individuals. The other options do not provide the same diagnostic advantage. Cultures are essential for confirmation but can be time-consuming and not always yield results in a timely manner. The immunoassay does not detect all fungal infections, making it specific to Aspergillus species rather than a broad range of fungi. Although the immunoassay may be easier to perform than a biopsy, the primary advantage