Non Invasive prenatal test (NIPT-Harmony)

NIPT is a screening test performed on a blood draw taken after 10weeks pregnancy and specifically screens for the common trisomies Trisomy 21, 18 and 13….more

Humans have 23 pairs of chromosomes which are DNA strands carrying genes. A trisomy occurs when there is an extra copy resulting in three chromosomes. These common occur at position 21 (Down’s syndrome) 18 and 13.

All of these trisomy result in a range of abnormalities many of which are not compatible with life.

This test has a detection rate of greater than 99% with a false positive rate for Trisomy 21 of less than 0.1% and for all trisomies combined a false positive rate of 0.15%

Genetic counselling is available for general questions or more specific questions regarding famial traits and inherited conditions through referral to the Genetics Dept at BC Women’s Hospital

This test has a detection rate of greater than 99% with a false positive rate for Trisomy 21 of less than 0.1% and for all trisomies combined a false positive rate of 0.15%

The test specifically targets the fetal fraction (ff) in the maternal bloodstream so occasionally a redraw is needed if there is insufficient fetal fraction (>4% needed) Some women may not have sufficient fetal fraction which does not necessarily mean anything bad.

Maternal weight is one factor, for example, that may affect the fetal fraction. For mothers over 200 lbs the fetal fraction gradually starts to decline which only affects the ability to do the test rather than indicating anything adverse.

Abnormal test results indicate the need for genetic counselling and further follow up with possible amniocentesis or chorionic villous sampling (CVS)

Prenatal Screening

Non Invasive prenatal test (NIPT-Harmony)