Harmony test – non-invasive fetal genetic test
Prenatal tests make it possible to check whether your child is developing correctly during pregnancy. If it has any abnormalities, they are detected by prenatal diagnostics – moreover, it allows to determine the cause of these abnormalities or to determine how to deal with the child during the next stages of pregnancy and after its birth. The group of prenatal tests also includes the Harmony test, i.e. a non-invasive genetic test from the mother’s blood.
What is the Harmony Test?
The Harmony test is the most sensitive and reliable of all non-invasive (i.e. completely safe for the foetus and mother) prenatal tests. It consists in cffDNA (free fetal DNA) analysis of a pregnant woman circulating in the blood.
Only a small amount of blood from a future mother is needed to perform the test. Then, the foetus’s DNA is isolated from the blood and examined in detail for disturbances,” says Magdalena Sikora, the portal’s geneticist.
The Harmony test has been carried out since the 10th week of pregnancy and can be performed by any pregnant woman, but in some situations it is particularly recommended. These include the woman’s age of 35 years, the father’s age of 55 years, the birth of a child with a genetic defect already in the past, the occurrence of a genetic defect in the immediate family, the presence of chromosome aberration in one or both parents, or incorrect ultrasound results. The Harmony test is also a great solution for contraindications to prenatal invasive diagnosis (such as a high risk of miscarriage or viral infection) – invasive tests require taking a sample directly from the foetus, which is associated with the risk of complications.
What does the Harmony test detect?
The diseases detected by Harmony include trisomes (Down syndrome, Patau syndrome and Edwards syndrome) and sex chromosome aneuploids (Turner syndrome, Klinefelter syndrome, XXX, XYY, XXY); thanks to this test parents can also get to know their child’s sex.
Fetal abnormalities are detected by a Harmony test with a sensitivity of more than 99%. The percentage of false positives is lower than 0.01%,” adds Magdalena Sikora.
Mother’s blood genetic testing is therefore the most sensitive of all non-invasive tests. The sensitivity of the others – USG, double, triple – is between 60 and 90%. In addition, the range of diseases detected for them is narrower compared to the Harmony test.
The Harmony test is performed in the course of single and twin pregnancies, conceived both naturally and using the in vitro method – in the case of a twin pregnancy with in vitro, the condition is to conceive the offspring after implantation of their own egg.
It should also be noted that despite the very high sensitivity of the Harmony test, it is considered (as is any other non-invasive prenatal test) as a screening test. In the event of an incorrect result, an invasive examination is necessary to determine the final diagnosis.