Which of the following methods can be used to detect rubella infection in children –
T4 cell count
Fetal hemoglobin
IgM antibody in fetal blood
IgA Antibody in fetal blood
Laboratory diagnosis

Isolation of virus in cell cultures of throat samples, urine or other secretions.
Normally, a maternal rubella antibody in the form of IgG is transferred to infants and is gradually last over a period of 6 months. Persistent beyond I year in an unvaccinated child suggests the diagnosis of congenital rubella.
Presence of IgM antibodies is diagnostic.
PCR for rubella RNA.