Varicella zoster antibody testing in the care of pregnant women exposed to varicella.

Appropriate use of varicella zoster immunoglobulin to prevent or ameliorate maternal or perinatal infection depends on accurate identification of varicella-susceptible women. Detection of fluorescent antibody to varicella zoster virus membrane antigen is an available means for identifying women exposed to varicella who are at risk for infection. During a 5 1/2-year period, 37 pregnant women who had been exposed to varicella and who had a negative or indeterminate history of prior varicella were tested for the presence of varicella zoster virus membrane antigen. Among the 17 women with a negative history, 12 (71%) had a positive test result and five (29%) had a negative test result. Among 20 women with undeterminant histories, 18 (90%) were immune and two (10%) were susceptible. Three additional women who were tested despite a history of varicella had positive varicella zoster virus membrane antigen test results. Overall, 81% of patients with a negative or uncertain history of varicella had serologic evidence of past varicella. One of six untreated seronegative women and one weakly positive woman developed disease. There was no instance of congenital varicella. Expeditious determination of varicella zoster virus membrane antigen or equivalent anti-varicella antibody status in pregnant women exposed to varicella appears to be a rapid, satisfactory method for determining who should promptly receive varicella zoster immunoglobulin passive immunization.