Which of the following tests would be used to diagnose HIV in an infant whose mother is HIV positive?
•Serological assays, generally used for adults, are not reliable in infants because maternal HIV antibodies can be present for up to 18 months.
•PCR (polymerase chain reaction) tests for HIV DNA and RNA. This test is externally validated and recommended for the diagnosis of infants. The sensitivity of this test at birth is 55% but increases to more than 90% by 2 to 4 weeks of age and to 100% at ages 3 months and 6 months.
•Particle agglutination is a test used to detect syphilis in adults.
•ELISA used to be the choice for diagnosing HIV followed by a confirmatory Western blot, but it's no longer recommended by the CDC as more accurate later generation tests are now available.