The Value of CMV and Rubella IGG Avidity Tests in the Diagnosis of Cytomegalovirus (CMV) and Rubella Infections in Pregnant Women

Abstract

ABSTRACTIgG avidity tests, which came on the scene recently with regard to most efficient use of time and early onset to the therapy, are considered in this study, and compared with Enzyme immunoassay(EIA). Serums of a total of 879 women in the first trimester of their gestations who referred to Dicle University, Faculty Hospital, Department of Gynaecology and Obstetrics in between the dates of 09 April 2002–09 May 2003 were evaluated with the classical method ELISA (Cobas Core II, Roche, USA), in terms of Rubella and HCMV IgG and IgM. Avidity tests were performed with (IgG avidity EIA. Well; Radim, Italy) commercial kits. 4 samples among the 8 that were positive for HCMV IgM and IgG were found to have low AIs (AI<35%), 2 samples to have intermediate AIs (AI 35–45%), and the other 2 to have high AIs (AI >45%). One of the 156 IgG positive serum samples had an intermediate AI (AI 35–45%), and 155 had high AIs. In the Rubella IgG avidity tests, 9 of the 13 IgM and IgG positive samples had low AIs (AI <50%), 1 had an intermediate AI (AI 50–60%), and 3 had high AIs (AI >60%). Only one of the 151 IgG positive samples had a low AI, whereas the remaining 150 had high AIs. If only avidity test is taken into consideration, gray region or low avidity test results especially negative for IgM with ELISA and showing a clear chronical pattern will be falsely interpreted in accord with an infection, if the results for these serums are new. IgG avidity test is useful in serums revealing suspected results in IgM ELISA test. Follow-up of patients with intermediate and low AIs and repeating tests in certain intervals, and examination of the amniotic fluid by PCR will be appropriate. As only IgG avidity test taken into consideration will cause unnecessary abortus and anxiety, use of single confirmation tests in such cases is not right. IgG avidity tests should only be used as confirmation tests in pregnant women.