Some experts continue to recommend follow-up antibody tests (1 antigen / antibody combination assay at > 18 months or, alternatively, 2 such assays done between 6 months and 18 months) to definitively exclude HIV infection and confirm seroreversion (loss of passively acquired HIV antibodies), especially if the infant was not in the low-risk category or was suspected to have exposure after birth (eg, from breast milk, percutaneous exposure, or sexual abuse).