The accuracy of cell-free DNA screening for fetal segmental copy number variants: A systematic review and meta-analysis

Background: The performance of cell-free DNA (cfDNA) screening for microscopic copy number variants (CNVs) is unclear. Objectives: This was a systematic review and meta-analysis to investigate the sensitivity, specificity and positive predictive value (PPV) of cfDNA screening for CNVs. Search Strategy: Articles published in EMBASE, PubMed or Web of Science before November 2022 were screened for inclusion. This protocol was registered with PROSPERO (23 March 2021, CRD42021250849) prior to initiation. Selection Criteria: Articles published in English, detailing diagnostic outcomes for at least 10 high-risk CNV results with cfDNA were considered for inclusion. Data Collection and Analysis: The PPV was calculated and pooled with random-effects models for double-arcsine transformed proportions, using cases with diagnostic confirmation. Overall sensitivity, specificity and a summary receiver-operating characteristics (ROC) curve were calculated using bivariate models. The risk of bias was assessed using QUADAS-2. Main Results: In all, 63 articles were included in the final analysis, detailing 1 591 459 cfDNA results. The pooled PPV was 37.5% (95% confidence interval [CI] 30.6–44.8), with substantial statistical heterogeneity (I² = 93.9%). Bivariate meta-analysis estimated sensitivity and specificity to be 77.4% (95% CI 65.7–86.0) and 99.4% (95% CI 98.0–99.8), respectively, with an area under the summary ROC curve of 0.947 (95% CI 0.776–0.984). Conclusions: Approximately one-third of women who screen high-risk for CNVs with cfDNA will have an affected fetus. This value is of importance for screening counselling.