alieden
commented
6 years ago - Add a NCVY vs fetal fraction graph and a NCVX vs fetal fraction graph with a prediction interval for XY-samples. Equations for the min and max lines will be sent via email to Maya. Theses graphs should follow the same set up as the NCVY vs NCVX graph with the current batch overlaying the previous included samples etc. These graphs have two main purposes. We have had a few false positive XY samples (XX-samples with a NCVY-value a bit over the set threshold) were a comparison between the fetal fraction and the NCVY values would have allowed us to identify them. Please note that we, in relation to this, also have decided to change the NCVY-threshold for XY-classification to a minimum of 20 (needs to be adjusted in the viewer). In addition, we sometimes have samples that end up to the left of the normal XY-samples in the NCVY vs NCVX graph. These are likely to be caused by low-level maternal X0 mosaicism in the blood (normal variation) and the idea is now to stop doing follow-up analysis for these samples if the NCVY-value is in accordance with the fetal fraction (reducing the chance of a X0/XY mosaicism in the fetus as possible explanation).