North American Registry of Midwives (NARM) Practice Exam

Which lab test is most commonly utilized as the initial assessment for HIV status?

1. Western blot test

2. Polymerase chain reaction (PCR)

3. Enzyme-linked immunosorbent assay (ELISA)

4. CD4 count test

The correct answer is: Enzyme-linked immunosorbent assay (ELISA)

The enzyme-linked immunosorbent assay (ELISA) is the most commonly utilized initial test for assessing HIV status because it is designed to detect antibodies to HIV in the blood. This test is favored for its sensitivity and ability to process a large number of samples, making it ideal for initial screening in both clinical and public health settings. An ELISA test is generally the first step because it allows healthcare providers to quickly identify individuals who may be infected with HIV. If the ELISA test is positive, follow-up confirmatory testing, such as the Western blot test, may be performed to validate the results. The Western blot, while specific and useful for confirmation, is not typically the first test used due to its complexity and lower throughput compared to the ELISA. The polymerase chain reaction (PCR) test is used for detecting the actual virus and is more suitable for specific circumstances, such as diagnosing individuals very early in the infection or monitoring viral load in someone already known to be HIV-positive. A CD4 count test measures the immune system's strength in individuals already diagnosed with HIV but does not indicate HIV status directly.