OC21.02: Lesion size affects the diagnostic performance of the International Ovarian Tumor Analysis (IOTA) logistic regression models, the IOTA simple rules and the risk of malignancy index to estimate the risk of malignancy in adnexal masses

Abstract

Objectives: Positive CMV IgM in the first trimester of pregnancy mandates IgG avidity assays to exclude or confirm primary infection in pregnancy. Methods: To correlate IgG avidity index actual values and trends with the risk of fetal infection. Sera were obtained from women in the first trimester of pregnancy. CMV serology was performed with the LIAISON CMV IgG kit and the LIAISON CMV IgM. Kit. Positive IgG (>0.6 UI/mL) and equivocal IgM (≥15 UA/mL and <30 UA/mL) or positive IgM (≥ 30 UA/mL) prompted CMV IgG avidity test. LIAISON CMV IgG Avidity assay and VIDAS CMV IgG Avidity assay were used in parallel and results were interpreted as recommended by the manufacturer (PI less than 3 months, PI more than 3 months, Intermediate). When at least one of the 2 avidity results was in favour of a PI dating back more than 3 months, the patient was reassured, in all other cases amniocentesis was recommended for prenatal diagnosis after 20 weeks. Results: 187 women (256 sera) had positive or equivocal IgM. Avidity index values were correlated (r2 = 0.646) but there was only 48% concordance in avidity test interpretations. 61 women (77 sera) had an avidity index low or intermediate in LIAISON or VIDAS CMV IgG Avidity assays. 15 of these 61 women (24.5%) had a positive CMV PCR in amniotic fluid retrieved between 19 and 25 weeks. Logistic regression of IgM levels and LIAISON avidity index values did not show any significant association with fetal infection but VIDAS avidity index values were inversely statistically associated with fetal infection (P = 0.002). Based on this logistic regression model the risk of fetal transmission was 70, 40% and 20% for VIDAS avidity index below 0.10, at 0.2, and at 0.4 respectively. Conclusions: These results could be useful for more accurate counselling of women presenting with positive CMV IgM in the first trimester to help them choose between amniocentesis at 20 weeks or ultrasound follow-up alone.