Random Massively Parallel Sequencing

Most comprehensively validated and most frequently and routinely employed method worldwide

According to the published data, the rMPS method, which is used in the PrenaTest® among others, is not only the most comprehensively validated method, but also the most frequently and routinely employed method worldwide.

One reason for the preferred use of the rMPS method in routine clinical testing is its high level of reliability. Based on the current data for Sequenom with 250,000 routine tests, the failure rate is currently 1.4%. The failure rate for the PrenaTest® is currently a mere 0.6% (as of Dec. 2014).

The accuracy of the tests also demonstrate how stable rMPS is. Sequenom has reported a sensitivity of 99.29% and a specificity of 99.99% for trisomy 21 (i.e. a false-positive rate of 0.01%) with a positive predictive value (PPV) of 99.04%. LifeCodexx AG has achieved similar values in routine testing. In the case of the PrenaTest®, sensitivity for fetal trisomy 21 is currently 100%, specificity is 99.97% (i.e. the false-positive rate is 0.03%), and the PPV is 98.29%. These values are based on the test results reported by physicians.

A sample calculation to illustrate the proportions of cell-free DNA

Assuming that the plasma sample of a pregnant woman contains 100 chromosome-21-specific fragments, about 10 of the fragments would be of fetal origin and 90 fragments would be of maternal origin in the case of a euploid fetus. In a comparable plasma sample from a pregnant woman with a fetus with trisomy 21, 15 out of 105 chromosome-21-specific fragments would be from the fetus and 90 from the mother. The PrenaTest® method reliably detects this difference of 1:1.05.