Factors affecting cell-free DNA fetal fraction and the consequences for test accuracy

Abstract

Introduction: Biological factors are known to influence the fetal fraction (FF) of cell-free DNA and may also influence the accuracy of non-invasive prenatal testing. Material and methods: NIPT from 5267 mixed risk women across three specialist clinics in Australia were analyzed. Multivariable regression analysis was used to determine whether maternal characteristics, ultrasound, and placental biomarkers affect FF and test accuracy. Results: FF ranged from 4% to 37% (mean 11.6%). Body mass index (BMI), gestation, and placental biomarkers were found to be significant factors associated with FF. For each unit increase in BMI, the logarithmically transformed FF, (lnFF), mean value decreased by ..