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