Cell‐free fetal DNA ‐based noninvasive prenatal testing of aneuploidy

Abstract

Key content Noninvasive prenatal testing (NIPT) uses cell-free fetal DNA (cffDNA) to test for aneuploidy, as opposed to noninvasive prenatal diagnosis (NIPD), which uses cffDNA to diagnose fetal sex, Rhesus D status and monogenic disorders. This classic review focuses on screening for aneuploidy. NIPT is a screening test and needs confirmatory invasive testing in cases of a high-risk (positive) result. NIPT demonstrates high sensitivities and specificities according to our recent meta-analysis, although it is less accurate for Trisomy 18, Trisomy 13, Monosomy X and sex chromosomal aneuploidies than for Trisomy 21. It is imperative that the implications of false positive and false negative results are investigated and considered in a clinical context. Learning objectives To be able to discuss NIPT with patients, including test accuracy and disadvantages. To be up to date with the implementation of NIPT in the National Health Service (NHS). Ethical issues NIPT requires careful counselling: patients may consider it a 'trivial' or routine blood test and may not fully understand the implications of a high-risk (positive) result. There are issues surrounding other diagnoses that NIPT can potentially reveal, including maternal cancers, maternal sex chromosome aneuploidies and milder fetal phenotypes.