Automated risk calculation for trisomy 21 based on maternal serum markers using trivariate lognormal distribution

Trisomy 21 is one of the most frequent type's chromosomal abnormalities. Generally, current methods for Trisomy risk assessment are divided into invasive and non-invasive techniques. Invasive methods are including amniocentesis, chorionic villus sampling (CVS), or percutaneous umbilical cord blood sampling (PUBS), but the drawbacks are expensive, time consuming and having risk of miscarriage, where else non-invasive methods are including ultrasound marker screening and maternal serum markers testing. Nevertheless, single evaluations on ultrasound markers are always not enough in terms of its accuracy, reliability and consistency. So, we proposed a new mathematical algorithm which combines three maternal serum markers using trivariate lognormal distribution to calculate automatically the probability or likelihood that a woman has an affected pregnancy or not. The developed algorithm was implemented into graphical user interface to act as computer aided e-diagnostic system. We have compared the results with published finding and found it is almost equally accurate.