A simple blood test can tell a lot about your baby. Small fragments of your baby’s DNA that circulate in your bloodstream allow for prenatal genetic screening. The non-invasive prenatal test (NIPT) lets the doctor know about the baby’s risk of having chromosomal abnormalities. Its results will decide on further testing and monitoring.
MomJunction tells you about non-invasive prenatal testing, how it is done, the possible results of the test, benefits, and more.
What is NIPT?
NIPT is a prenatal blood test to screen for fetal aneuploidy disorders such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18) and Patau syndrome (trisomy 13) that cause intellectual disability or significant birth defects.
The test is also referred to as cell-free DNA screening, informaSeq, MaterniT21, Harmony, Panorama or Verifi. It screens for conditions that occur due to chromosomal abnormalities.
NIPT is a screening test and not a diagnostic test, which means it does not confirm if your unborn baby has a chromosomal condition. A normal NIPT result does not guarantee a healthy baby, and an abnormal result does not always mean the baby has a specific condition. In the case of an abnormal result, the doctor would suggest further testing.
Chorionic villus sampling (CVS) and amniocentesis are the only two diagnostic tests available for detecting Down syndrome and other chromosomal abnormalities (1).
Who Goes Through An NIPT?
NIPT is recommended if:
- You previously had a baby with chromosomal abnormality
- There is a family history of chromosomal conditions
- Ultrasound or other prenatal tests have detected a problem
But, this is not a test of choice if there are:
- Fetal anomalies in the ultrasound
Also, this test is not recommended if –
- You are carrying twins or multiples
- You had a blood transfusion, stem cell transplantation or immunotherapy for over three months, or if you are undergoing a heparin therapy
- You are having genetic abnormalities (2)
When Is NIPT Done?
It can be done as early as ten weeks into gestation, which is earlier than any other prenatal screening or diagnostic tests. You will receive the results in a week or two.
How Is The Test Done?
The procedure involves drawing blood, which is then sent to the laboratory for analysis. The lab technician looks at the cell-free DNA (cfDNA), the baby’s DNA fragments in the mother’s blood, for signs of abnormality.
Your healthcare practitioner will pair the results of the test with other findings from the first-trimester ultrasound scan and nuchal translucency screening for further diagnosis.
What Are The Possible Results Of NIPT?
Low or negative risk means that it is unlikely your child is at a risk of the condition that NIPT screens for.
High or positive risk indicates that there is an increased risk of a particular condition. Your doctor recommends genetic counseling and further diagnostic testing.
Inconclusive or unclear results is a rare occurrence. It is also referred to as No Result NIPT or “Redraw Request”, and means that the outcome is inconclusive or not reportable. It usually happens when the test is done very early, i.e., much before ten weeks, and if the mom-to-be is obese. NIPT may also not yield a conclusive result in the case of:
- technical errors in the laboratory
- differences in the maternal blood sample
In this case, your doctor will recommend a re-test, or diagnostic testing along with genetic counseling (3).
False positive and false negative results are also possible. Therefore, the result can be low or negative risk, but a baby could be born with an abnormality. Likewise, the result may be high or positive risk, but a baby may not carry any abnormality (4).
How Accurate Is NIPT?
NIPT is more accurate than the traditional first-trimester blood screenings (such as blood work or quad screening). The test is 90 to 99% accurate with false positive rates of less than 1%. It means there is a very less chance that your practitioner would recommend follow-up tests such as CVS or amniocentesis (3).
Thus the test is beneficial because it helps know about the likely abnormalities in the baby.
What Are The Benefits Of NIPT?
Here are some ways NIPT could be good for the baby:
- The early prenatal testing helps you decide about the future course of action if the fetus is diagnosed with abnormalities.
- High accuracy rate of up to 99%. Eliminates the need for further diagnostic tests in most cases.
- Finds the Rh blood type and gender of the baby.
- Detects chromosomal sex conditions such as Klinefelter syndrome (47, XXY) and Turner syndrome (45, X), but with lesser accuracy.
However, non-invasive prenatal testing also has certain limitations.
Drawbacks of NIPT
Let’s see what they are:
- Detects only a limited number of conditions
- There is always a risk of false-positive results, and a trained professional is needed for interpreting the results accurately.
- It will not work if you have a high BMI or are expecting multiples (5).
- Expensive since many insurance companies cover it only for women over 35 years
How Much Does NIPT Cost?
The prices might vary. The cost of NIPT ranges between $800 and $2000 in the US, and between $500 and $1500 elsewhere (6). Most insurance companies cover only a portion of the cost. We advise you to check with your insurance company about its coverage.