Events

Lecture - First trimester screening versus non-invasive prenatal testing (NIPT)

FML at EOFF 2013 in Dubai

First trimester screening versus non-invasive prenatal testing (NIPT)

PD. Dr. med. Michaela Jaksch
Freiburg Medical Laboratory, Dubai, UAE

Several tests with multiple components are being used for the antenatal  screening of  trisomies, especially trisomy 21.

Triple test (second trimester screening) screening started in 1990 using three biochemical markers together with the maternal age for the risk calculation. A significant improvement in the risk assessment has been achieved by introducing the first trimester screening (FTS) in the year 2000. The algorithm uses mainly the maternal age, the nuchal translucency (NT) together with 2 biochemical markers, free beta-HCG and PAPP-A.

NIPT tests based on the detection of cell free fetal DNA in maternal blood has improved significantly over the past 3 years. The currently used  test systems detect trisomies 21, 18 and 13 as well as  X and Y. The specificity is reported to be >99%. The sensitivity to detect T21 is >99%, T18 > 97%  and T13 >80%. The sensitivity for detecting the female gender is >90%, the male gender is recognized with a sensitivity of >99%.

NIPT is especially indicated if the triple test or the first trimester screening indicate an increased risk for T21 or T18, at increased maternal age and in cases of anxiety towards invasive procedures (AC / CVS).

NIPT is not the method of choice if there are specific fetal anomalies on ultrasound, in triplet pregnancies, in vanished twin and in cases of known genetic anomalies that cannot be diagnosed by NIPT.

This lecture will provide an updated overview on NIPT/FTS. The importance of genetic counseling (to identify family history risk factors) and the continued importance of ultrasound monitoring as well as invasive prenatal diagnosis in the new era of NIPT are discussed.