Diagnostic HIV Laboratory

Pediatric HIV PCR Testing Service

The Pediatric HIV PCR Testing Service was implemented by the Department of Health to assist in the diagnosis of perinatal HIV transmission. This service is not intended as a screening test for HIV, but rather to definitively diagnose HIV infection in infants who are known to be HIV antibody positive or whose mothers are known to be positive. HIV-antibody tests may not establish infection in infants younger than 12 months of age due to transfer of maternal antibodies to the newborn. Assays to detect virus, such as HIV DNA PCR, should be used for diagnosis of infection in exposed infants.

HIV infection can reasonably be excluded among HIV exposed children with two or more negative DNA PCR tests performed at age greater than one month and one of those being performed at or greater than four months. An infant is diagnosed as infected at any age by two positive DNA PCR tests performed on separate specimens.

The testing recommendations are written, reviewed and updated on a regular basis by the New York State Committee for Care of Children and Adolescents with HIV/AIDS, a group responsible for developing standards for the diagnosis and care of HIV-exposed and positive children. Laboratory guidelines were first published in the MMWR 1998; 47(RR4-4):1-43 for the diagnosis of perinatal HIV transmission and are reviewed and updated on a regular basis. More recent guidelines were published by the Committee in December, 2004. Please consult www.hivguidelines.org for updates.

Recommendations on Timing of Testing

Depending upon the age of the infant when the first specimen is submitted to the laboratory, two to four specimens per infant may be necessary to definitively diagnose the infant's HIV infection status. Any infant at any age with a positive PCR should have another test as soon as possible to confirm the positive result. No further testing is needed after the second positive result.

Recommendations for DNA PCR testing are as follows:

• Initial testing by age 48 hours; this identifies infants infected in utero
• At two weeks of age
• At age one month
• At age 8 to 10 weeks
• Final DNA PCR specimen at greater than 4 months of age

Note: Negative DNA PCR tests drawn when the infant is less than 28 days do not exclude HIV infection, particularly if the infant has been exposed to antiretroviral medication in utero or after birth.