Limitations of the Prequel® test
In a very limited number of cases, the Prequel® test cannot be administered successfully. This usually occurs when the amount of fetal DNA (cffDNA) is too small to provide a result. Other reasons for test failure include failure to report the presence of a donated egg, the presence of a resorbed twin and previously undiagnosed chromosomal abnormalities (usually benign) in the mother.
In such cases, we recommend that venous blood from the mother be drawn again at a slightly later stage of the pregnancy to repeat the Prequel® test. The majority of cases have been successfully processed after a repeat blood sampling.
If the test is not performed successfully after a repeat sampling, the customer will be fully refunded. 24 hours must have elapsed since the last administration of low molecular weight heparin therapy.
Mosaicisms, partial trisomies and translocations
No NIPT method based on the cffDNA test can detect chromosomal mosaicism, partial trisomy or translocations.
Multiple pregnancies
Prequel® cannot be used to test for chromosomal abnormalities in 3 or more fetuses. In case of triplets and multiple pregnancies, invasive methods are recommended.