relationship of igg avidity index and igm levels for the differential diagnosis of primary from recurrent cytomegalovirus infections

since the incidence of symptomatic congenital cytomegalovirus infection is low (~0.05%) and risk factors are not well defined, it is difficult to develop strategies for prevention. the aim of this study was to recognise the utility of specific immunoglobulin g avidity analysis for distinguishing primary infection from past/recurrent infection. sera from 50 women with cytomegalovirus specific immunoglobulin m antibodies without proven seroconversion and infants born to these women were tested for presence of immunoglobulin m antibodies by commercial enzyme immunoassay. for cytomegalovirus specific immunoglobulin g avidity, sera were measured by commercial kit according to manufacturer's recommendations. among 50 sera form mothers, 26 showed the presence of immunoglobulin m antibodies out of which 15 had low avidity antibodies. out of 50 sera from children, 18 showed the presence of immunoglobulin m antibodies. out of these 18 sera from children, 12 were symptomatic, which all showed the presence of low avidity antibodies. the results showed that an avidity index