Fig. 1

College of American Pathologists (CAP) 2018 Educational Exercises: analysis of the reported decimal gestational age and decimal maternal age. (a) Noninvasive prenatal testing (NIPT) challenge is on the horizontal axis and the reported decimal gestational age is on the vertical axis. The data have been dithered left and right for visibility. For challenges 01, 02, 04, and 06, the date of the ultrasound was the same as the sample draw date and all participants provided correct responses. For samples 03 and 05, the ultrasound had been performed prior to the sample draw date. Those laboratories incorrectly reporting the lower gestational age (e.g., 11.6 weeks rather than 13.3 weeks for sample 03) are incorrect (indicated by X). Extreme values are also indicated by an X. (b) NIPT challenge is on the horizontal axis and the reported decimal maternal age is on the vertical axis. The decimal maternal age should be determined at the estimated date of delivery, several months later than the sample draw date. For all samples, a subset of laboratories incorrectly computed the maternal age. For sample 01, for example, the correct response was 25.7 years (higher set of observations, O) while the incorrect response was 25.3 years (lower set of observations, X). Any extreme results are also indicated by an X.