EP18.21: Accuracy of fetal cell‐free DNA to predict selected chromosomal anomalies among women experiencing miscarriage

To evaluate the accuracy of fetal cell-free DNA (cfDNA) to predict selected chromosomal anomalies among women experiencing miscarriage. Medline, Embase, Cinahl and Web of Science databases were searched electronically up to February 2024. The overall accuracy of cell-free fetal DNA (cfDNA) to predict the selected chromosomal anomalies among women experiencing miscarriage was assessed computing summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR–) and diagnostic odds ratio (DOR), using the hierarchical summary receiver–operating characteristics (HSROC) model [1]. Rutter and Gatsonis HSROC parameterization was used because it models functions of sensitivity and specificity to define a summary ROC curve, and its hierarchical modelling strategy can be used for comparisons of test accuracy when there is variability in threshold between studies [2]. However, when the number of studies is small, the uncertainty associated with the estimation of the shape parameter could be very high, and models may fail to converge. Thus, for all meta-analyses in which less than four study estimates could be pooled, the DerSimonian-Laird random-effect model was used. Seven studies including 791 pregnancies were included in the analysis. Sensibility and specificity for overall chromosomal anomalies were 81.7% and 97.6% respectively, with LR+ of 33.6, LR- of 0.19 and DOR od 179. Sensibility was highest for T21 and T18 (100%) and lower for T13 (88.9%), X0 (81.8%) and autosomal trisomies (75.8%). Specificity was 100% for all type of chromosomal anomalies assessed, except for autosomal trisomies (99.4%). Sensibility and specificity for CNVs were 60% and 100%, respectively. Cell-free DNA is an accurate tool to predict chromosomal anomalies among women experiencing miscarriage, with the highest accuracy reported for the most common trisomies.