Non-invasive Prenatal Screening or Testing (NIPS / NIPT)
During pregnancy, free segments of DNA originating in the placenta and largely identical to the fetal DNA are released into the mother’s blood.
The NIPT/NIPS test is a blood test performed during pregnancy designed to detect mutations in the fetus’s genetic material that is present in the mother’s blood that may be attributed to chromosomal abnormalities in the fetus, such as Down syndrome.
The NIPT/NIP test is a screening rather than a diagnostic test. It cannot replace an amniocentesis; in other words, if the test raises the suspicion of a chromosomal abnormality in the fetus, the findings should be diagnosed through chorionic villi sampling (CVS) or amniocentesis. It also does not test the chromosomes at the level of discrimination and detail that is tested in amniotic fluid.
It is now possible to perform a basic or expanded test. The difference between them is the number of syndromes being tested.
Target audience
The NIPS/NIPT test is suitable for all women (single or twin pregnancy) and can be performed at low or increased risk of chromosomal abnormalities in order to reduce the existing risk. It is important to emphasize that in situations in which there is a known increased risk, a CVS or amniocentesis should be performed.
Advantages of the test
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Identification of common chromosomal abnormalities
The latest data about the test indicates that it is highly sensitive in detecting common chromosomal abnormalities: trisomy 21 (over 98%), trisomy 18 (approximately 94-98%), and trisomy 13 (over 99%). It can also be said that its capacity for positive prediction of these abnormalities is significantly high in comparison with other screening tests that are available (such as the Triple Test in the first and second trimesters).
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Identification of abnormalities in the sex chromosomes
The NIPT/NIPS test can also discover a high risk of common abnormalities in the sex chromosomes, such as Turners syndrome or Kleinfelter syndrome.
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Highly safe
The NIPT/NIPS test is a blood test and poses very little risk to the mother or fetus.
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Early test
The test can be performed from Week 10 of the pregnancy, so that even if an abnormal result is received, there is time to perform a diagnostic test.
Disadvantages of the test
- Screening test only: The test cannot definitively determine whether the fetus has a chromosomal abnormality. In other words, if the test raises a suspicion of a chromosomal anomaly in the fetus, a recommendation will be made that you undergo a diagnostic test. There may be situations in which the test raises an increased risk of chromosomal abnormality, but the fetus is actually revealed to not suffer from the abnormality.
- Does not detect all defects and problems: The test does not test the chromosomes present in the fetus at the level of distinction and detail of a diagnostic test, such as in CVS or amniocentesis. The test does not detect congenital structural defects or disorders in organ or tissue function (such as intellectual delay, autism, deafness or blindness, etc.). If you are interested in a broad range of diagnoses of syndromes and genetic diseases, you can consider undergoing other tests that are relevant.
- Lower reliability in higher-order pregnancies: There is currently insufficient information to assess the efficacy of the test in pregnancies involving triplets or higher-order multiple pregnancies. In addition, in cases of fetal reduction or missed abortion (such as a pregnancy that begins as a twin pregnancy but one fetus is absorbed or stops developing), the test should not be performed due to an increased risk of false positive results.
- Identifies the sex of the fetus: If the test includes sex chromosomes, you may be informed of the sex of the fetus (even if you did not want to know).
- Situations in which there is no result: On rare occasions in which, for various reasons, there isn’t sufficient amount of fetal DNA to perform the test, and as such no result will be obtained. In these cases, the recommendation is that you repeat the test.
- Other limitations: There are several situations that constitute a limitation for the test, for example: pregnancy from egg donation, a woman who has developed cancer, a woman who has undergone an organ or bone marrow transplant, a woman who received a blood donation in the month preceding the test. In these situations, the recommendation is that you first consult the company performing the test.
- The result refers to a health condition of the mother and not the fetus: On rare occasions, the test indicates a risk of a chromosomal abnormality in the mother or risk of maternal diseases (such as benign or malignant tumors). These situations require genetic counseling.
Important to emphasize: If in any case you are planning to undergo a diagnostic test (CVS or amniocentesis), the contribution of the test is less significant for you, other than the fact that it can be performed at an earlier stage.
Date of the test
From Week 10 of pregnancy. Can be performed at any stage during the pregnancy.
Course of the test
This is a regular blood test performed on the mother.
Test results
In general, the results are received within 10–14 days from the test date.
The result will be sent to the physician who referred you to the test and will be sent to you in writing.
If the result is abnormal, you will receive a referral to genetic counseling and a recommendation to undergo a diagnostic test.
Financing the test
The test is not included in the health services basket but is performed privately.
You can receive reimbursement for some of the cost of the test from the supplementary insurance of the HMO (the amount of the reimbursement depends on the plan in which you are insured) or from private insurance (if you have any).