Which test, in addition to viral load, is used to assess immune status in HIV patients?

• A. CD4 count
• B. HIV antibody titer
• C. White blood cell count
• D. Platelet count

Answer: (A)

Immune status in HIV is most accurately assessed by the CD4 T-lymphocyte count. This measure reflects how well the immune system’s helper cells are functioning, which is crucial because the risk of opportunistic infections rises as CD4 numbers fall. Viral load tells you how actively HIV is replicating, but it doesn’t directly indicate immune competence. A person can have a suppressed viral load yet still have low CD4 counts, indicating immune suppression and ongoing infection risk. Clinically, CD4 counts guide prophylaxis decisions (for example, starting Pneumocystis jirovecii pneumonia prevention when CD4 is below 200 cells/mm³) and help stage disease and monitor immune recovery on therapy. Normal CD4 counts are roughly 500–1500 cells/mm³, with lower numbers signaling greater immune compromise; in children, the CD4 percentage can also be used because absolute counts vary with age.

HIV antibody titer shows exposure or serostatus rather than current immune function. White blood cell count and platelet count are nonspecific and can be influenced by many factors, not reliably indicating the immune status related to HIV.