Non-Invasive Prenatal Testing (NIPT)

About the NIFTY Test

The NIFTY Test is a non invasive blood test for pregnant women from 10 weeks of pregnancy, with a 99% detection rate for Down Syndrome, Edward Syndrome, Patau Syndrome and some other genetic conditions.

How does it work?

We know that about 10% of the DNA circulating in a pregnant woman’s blood is from the pregnancy itself. So, by taking a blood sample from the mother, it’s now possible to identify conditions in the baby.

Who is it suitable for?

The NIFTY Test is suitable for any pregnant woman with a singleton or twin pregnancy (including IVF and ICSI pregnancies with self or donor eggs). Usually, the test is most suitable for:

  • Women over 35 who are concerned about their age related risk of Down Syndrome and other Trisomies
  • Women under 35 who want a safe, reliable, early and accurate test for Down Syndrome
  • Women who have an increased risk or “High Risk” result from a Combined Test or Nuchal Translucency scan but wish to avoid unnecessary CVS or amniocentesis and their risk of miscarriage
  • Women who have an increased risk or “High Risk” result from a Triple test or Quad test but wish to avoid unnecessary CVS or amniocentesis and their risk of miscarriage
  • Women with a previous pregnancy with a baby with Down Syndrome, Patau Syndrome or Edward Syndrome

What does it test for?

Trisomy 21 is the most common trisomy at the time of birth. Also called Down Syndrome, it is associated with moderate to severe intellectual disabilities and may also lead to digestive disease and congenital heart defects and other malformations.

Trisomy 18 (Edwards Syndrome) and Trisomy 13 (Patau Syndrome) are associated with a high rate of miscarriage. These babies are born with severe brain abnormalities and often have congenital heart defects as well as other birth defects. Most affected individuals die before or soon after birth and very few survive beyond the first year of life.

There is an extended version of the test (NIFTY Plus) which also screens for:

  • Sex Chromosome Aneuploidy (95% detection rate)
  • Turner Syndrome (XO), XXY, XXX, XYY
  • Deletion Sydromes (Detection rate not validated): Cri Du Chat (5p), 1p36, 2q33.1, DiGeorge 2 (10p14 but not 22q11 Di George mutation, 16p12.2, Jacobsen (11q23), Van Der Woude (1q32.2), Prader Willi/Angelman (15q11.2)

We recommend the NIFTY Plus Test because of this wider screening.

Can it tell my baby’s sex?

The test will also be able to determine the baby’s sex in most cases of single pregnancies with an accuracy of about 98%.

What is the chance the test will get a result?

Recent studies have shown that the failure rate for the test is affected by the mother’s weight as it affects the amount of fetal DNA available. Success rates are over 99%.

What about twins?

If the test shows LOW RISK then neither twin is likely to have Trisomy 21, 18 or 13. If the test shows HIGH RISK then ONE or BOTH babies may have the condition and amniocentesis would be advised to check each baby.

How accurate is the test?

Clinical studies have shown exceptional accuracy for detecting fetal trisomy. If you have had a blood transfusion within the last 12 months, stem cell therapy, immunotherapy or an organ transplant , this may invalidate the test results.

A HIGH RISK result is indicative of a high risk for a trisomy. The test identifies more than 99% of fetuses with trisomy 21, 18 and 13 ie it misses 1 in 100 affected babies. After the test, the number of women required to have a CVS or an amniocentesis is less than 1%. It is important to note that if the test results show there is a HIGH risk that the fetus has trisomy 21, 18 or 13 it does not mean that the fetus definitely has one of these defects as there is a 1:2000 chance the baby may not have the condition. For this reason, in the event of a high risk (or positive) result, follow-up testing by an invasive procedure is recommended.

In the same way if the test results show that there is a LOW RISK that the fetus has trisomy 21, 18 or 13 it is unlikely that the fetus has one of these defects. However there is a very small risk that not all trisomy fetuses will be detected.

All results should be interpreted by a clinician in the context of clinical and familial data: patients should continue with their usual scan appointments following testing.

How long will it take to get results?

The standard NIFTY test is typically reported within 10 working days. Occasionally (2.8% of tests which are done) if there is not enough fetal DNA in the original blood sample then a repeat blood test may be required within a week of the original test at no extra cost.

Are there any risks to the pregnancy from the NIFTY Test?

No. The testing is non-invasive: it involves taking a blood sample from the mother. The pregnancy is not put at risk of miscarriage, or from other adverse outcomes that are associated with invasive testing procedures such as CVS or amniocentesis.