Internal Medicine II Practice Test 2026 – Comprehensive Exam Prep

The pattern being tested is when infections are not only recurrent but also unusually prolonged, suggesting inadequate immune clearance of bacteria. In adults, three or more bacterial infections that last four weeks or longer indicate a potential immunodeficiency because a healthy immune system typically clears uncomplicated bacterial infections more quickly. This prolonged, repeated infection pattern points toward problems with antibody-mediated defense (humoral immunity) or related immune pathways.

While having two sinus infections per year or several infections treated with antibiotics can occur in healthy individuals, they are less specific and don’t by themselves imply an immune defect. The emphasis is on the combination of multiple episodes plus long-lasting episodes, which raises concern for an underlying immunodeficiency.

If this pattern is observed, it warrants immunologic evaluation, including quantitative immunoglobulins (IgG, IgA, IgM), assessment of antibody responses to vaccines, and possibly lymphocyte subtyping and HIV testing, to identify deficiencies and guide management.