Does NIPT screen for Down syndrome?

NIPT primarily looks for Down syndrome (trisomy 21, caused by an extra chromosome 21), trisomy 18 (caused by an extra chromosome 18), trisomy 13 (caused by an extra chromosome 13), and extra or missing copies of the X chromosome and Y chromosome (the sex chromosomes). The accuracy of the test varies by disorder.

How accurate is NIPT for Down syndrome?

NIPT is quite accurate for Down syndrome (99%) and for trisomy 18 (97%). It is less accurate for trisomy 13 (87%). In all cases, the results should not be considered certain unless confirmed by diagnostic testing. Two diagnostic procedures can usually confirm or disprove the results of NIPT.

How often is NIPT wrong on Down syndrome?

FTS has a detection rate (sensitivity) of 70-80% for trisomy 21, indicating a false-negative rate of 20-30%. This means that in one of 4 pregnancies with trisomy 21, a child with Down syndrome is born to parents that felt reassured by FTS.

What percentage of NIPT tests are positive?

Numerous studies have shown sensitivity rates for NIPT was approximately 99% with false positive rates below 1% and the positive predictive value is limited to 40% to 90%.

What happens if NIPT is positive?

If you have a positive NIPT result, your healthcare provider will likely order additional diagnostic tests. In some cases, these diagnostic tests reveal that the baby doesn’t have a chromosomal abnormality after all.

What happens if NIPT test is positive?

What causes false positive for Down syndrome?

Undetected tumors and mosaicism, in which cells within the mother carry a different genetic makeup, can also be responsible. Several large studies have confirmed that these cell-free DNA, or cfDNA, tests have a detection rate of 99 percent for Down syndrome, with a false-positive rate of as low as 0.1 percent.

Which test is more accurate for Down syndrome?

DNA blood test ‘more accurate for detecting Down syndrome than standard methods’ In a study of almost 16,000 pregnant women, researchers found that a cell-free DNA blood test carried out between 10-14 weeks gestation was more effective for diagnosing Down syndrome than standard screening methods.

What can cause a false-positive for Down syndrome?

What do I do if my NIPT test is positive?

If the result is ‘positive’, ‘abnormal’ or ‘high risk’, this means your baby is likely to be affected. If you have an abnormal NIPT result, a diagnostic test such as CVS or amniocentesis can confirm the result. You should discuss your options with your doctor, midwife or genetic counsellor.

Which parent carries the Down syndrome gene?

Being carriers of the genetic translocation for Down syndrome. Both men and women can pass the genetic translocation for Down syndrome on to their children.