Maternal HIV antibodies usually persist for nearly 9- 12 months in the infant. In some children, they may persist for as long as 18 months.
Following table shows the various tests available for diagnosis of HIV infection and their relevance for children aged < 18 months.
|HIV antibody||No||False +ve due to |
|HIV DNA PCR||Yes||98 % sensitive from |
6 weeks of age
|HIV p24 Antigen||Yes, but||Lower sensitivity than |
PCR (27 % at 6 weeks)
|HIV viral culture||Yes, but||Costly, result takes |
2- 4 weeks,
not readily available
As per the Early Infant Diagnosis (EID) protocol of NACO, HIV exposed infants are tested for HIV infection status as follows:
- The first HIV DNA PCR test for HIV-1 infection using a Dried blood spot (DBS) method at 6 weeks of age. If the DBS test is positive for HIV, the test is repeated on another DBS sample as early as possible for confirmation.
- If the first PCR is negative (before 6 months of age), the child is screened for HIV antibodies (Rapid test) at 6 months age. Infants testing positive on rapid test are re- tested with a PCR test using DBS
- DNA PCR can be repeated earlier if the infant becomes symptomatic
- If the child is breastfed and initial PCR tests are negative, re-testing is carried out 6 weeks after cessation of breastfeeding
- Children aged ≥ 18 months are tested according to the national adult testing strategies – Two positive HIV antibody test results (done sequentially) in a clinically symptomatic child or Three positive HIV antibody test results (done sequentially) in a clinically asymptomatic child indicate HIV infection in the child.