What results can you expectfrom the Prequel® test?

What results can you expectfrom the Prequel® test?

The risk of Down syndrome in pregnant women aged 35 is 1:360

Learn more

There are three possible results of the Prequel® prenatal test:

A high-risk result. This means that the chance of a chromosomal abnormality is higher than usual. Therefore, further testing is recommended.

A low-risk result. This means that the risk of chromosomal abnormalities is low for the abnormalities tested for. The usual course of pregnancy management is recommended. No result. In a small percentage of cases, the Prequel® test cannot produce a result.

Further blood tests and new tests or diagnostic tests may be recommended. The chance that the Prequel® test can be performed successfully depends largely on the amount of cell-free fetal DNA (cffDNA) in the mother’s blood. The percentage of cffDNA also depends on the length of the pregnancy (the earlier the pregnancy, the lower the percentage of cffDNA), as well as the mother’s weight (the higher the mother’s weight, the less cffDNA from the baby will be isolated).

Negative (normal) test result

The Prequel® test determines the risk of trisomy 21, 18 and 13 and, upon request, the risk of numerical changes in the X and Y sex chromosomes, as well as other chromosomes. In the case of a negative test result without pathological ultrasound findings, the presence of the tested disorders in the baby can be excluded with a high level of accuracy.

All NIPT methods have limitations when it comes to determining mosaicism and changes in chromosome structure. The Prequel® test examines the most common chromosomal disorders, so it cannot identify physical disorders in the baby; therefore, a negative (normal) test result cannot exclude the possibility of other disorders in the fetus. A large number of these disorders can be identified by a precise ultrasound examination, most commonly from the 12th week of pregnancy. Genetic tests, such as the Prequel® test, can never replace an ultrasound exam.

Positive (abnormal) test result

If the Prequel® test shows a positive (abnormal) result, there is a high probability that the fetus has one of the chromosomal abnormalities tested. However, since the test can give a false positive result, the positive (abnormal) result must always be confirmed by another diagnostic method, an invasive method (chorionic villus sampling, amniocentesis or cordocentesis).

A further chromosomal analysis of these samples can then provide a de nitive diagnostic result. As part of the information process, the geneticist at PoliGenetics Lab will explain all the possible effects of the chromosomal disorder and provide you with information on further diagnostic testing options. In addition, in the event of a positive test result, PoliGenetics Lab will cover the costs of the invasive method.

Sign In