OD ratio < 0.90 indicates no detectable Rubella IgG antibody.
OD ratio 0.91 - 1.09 is equivocal for Rubella IgG antibody. Suggest a new specimen be collected and re-tested.
OD ratio > 1.10 is positive for Rubella IgG antibody. In asymptomatic patients, including prenatal screens, a positive value is consistent with previous infection or immunity.
A single specimen is of limited diagnostic value in documentation of an acute or concurrent infection