The CMV IgG avidity (AviDx) test identifies cytomegalovirus (CMV) infection in pregnant women, and distinguishes between primary and non-primary or reinfection. Primary infection poses serious mortality and morbidity risk for the fetus, while reactivation or reinfection rarely has debilitating sequelae.
Because avidity increases or matures over time following primary infection, the AviDx test can be used to approximate the time of first infection. Testing by this company has demonstrated that a high CMV IgG avidity value can exclude, with >95 % accuracy, the possibility that infection occurred within the previous 4 months. Knowing the approximate time of infection can help physicians determine if a fetus is at risk for infection or more likely protected by maternal antibodies developed before conception.
Approximately 50% of women who become infected with CMV during pregnancy transmit disease to their infants, with potentially devastating consequences including death and permanent disability. Women with CMV reinfection or reactivation, on the other hand, transmit disease at a far lower rate of 0.5%, and debilitating sequelae are extremely rare.
Testing for CMV antibody is typically ordered as part of the standard prenatal laboratory workup. The CMV IgG avidity test is currently available only from this company’s reference laboratory.
Focus Technologies
www.focusanswers.com
Keywords: prenatal test, infectious disease
