Pregnancy is an exciting time for expecting parents. It is a time when parents eagerly anticipate the arrival of their new baby. Prenatal testing is an important part of ensuring a healthy pregnancy. In recent years, non-invasive prenatal testing (NIPT) has emerged as an alternative to traditional prenatal testing methods. In this blog, we will explore what NIPT is, how it works, its benefits, and limitations.
What is non-invasive prenatal testing (NIPT)?
Non-invasive prenatal testing (NIPT) is a screening test that can detect genetic abnormalities in a developing fetus. Unlike traditional prenatal tests, such as amniocentesis or chorionic villus sampling (CVS), which are invasive and carry a risk of miscarriage, NIPT is a non-invasive test that uses a blood sample from the mother.
NIPT looks for fragments of fetal DNA in the mother's blood. The test can detect the presence of certain genetic conditions in the fetus, such as Down syndrome, trisomy 18, and trisomy 13, as well as certain sex chromosome abnormalities.
How does non-invasive prenatal testing (NIPT) work?
NIPT is a simple and painless procedure. It involves taking a small sample of the mother's blood, which is then analyzed in a laboratory. The laboratory uses advanced technology to isolate and analyze the fetal DNA in the mother's blood.
The test looks for specific genetic markers associated with certain genetic conditions. If the test detects an abnormality, the mother will be referred for further testing, such as amniocentesis or CVS, to confirm the diagnosis.
What are the benefits of non-invasive prenatal testing (NIPT)?
One of the main benefits of NIPT is that it is a non-invasive test that carries no risk to the fetus. Traditional prenatal testing methods, such as amniocentesis and CVS, carry a small risk of miscarriage, which can cause anxiety and stress for expecting parents.
NIPT is also a more accurate test than traditional screening tests. NIPT has a high sensitivity and specificity, meaning it can detect a wide range of genetic conditions with a low rate of false positives or false negatives.
NIPT can also provide early detection of genetic conditions, which can allow parents to make informed decisions about their pregnancy. If a genetic condition is detected, parents can prepare for the birth of their child and make informed decisions about their medical care.
What are the limitations of non-invasive prenatal testing (NIPT)?
While NIPT is a highly accurate screening test, it is not a diagnostic test. If an abnormality is detected, further testing is needed to confirm the diagnosis.
NIPT is also more expensive than traditional screening tests. Some insurance companies may not cover the cost of the test, which can make it difficult for some families to afford.
Finally, NIPT is not a test for all pregnant women. The test is recommended for women who are at higher risk for having a baby with a genetic condition, such as women who are over 35 years of age or who have a family history of a genetic condition.
Conclusion
Non-invasive prenatal testing (NIPT) is a safe and accurate screening test that can detect genetic abnormalities in a developing fetus. NIPT is a valuable tool for expecting parents who want to make informed decisions about their pregnancy. However, it is important to understand the limitations of the test and to discuss the benefits and risks with a healthcare provider before deciding to undergo the test.
Non-invasive Prenatal Testing Results Explained
What does a low-risk result mean?
A low risk means - no anomaly detected for that specific condition which is under study. A LOW-RISK result does not guarantee that a fetus is unaffected by a chromosomal or genetic condition as False Negatives are possible, though the probability is quite low with Concepto-NIPT (VeriSeq NIPT Solution v2)
What does a high-risk result mean?
A high risk means - An anomaly is detected for that specific condition which is under study. Some non-aneuploid fetuses may have HIGH PROBABILITY results i.e., false positives may occur, though the probability of this occurrence is very low. In the event of a HIGH-RISK result and/or other clinical indications of a chromosomal condition, confirmatory testing is necessary for diagnosis.
What is fetal fraction?
Cell-free DNA (cfDNA) in the peripheral blood of pregnant women consists of maternal DNA and a small portion of DNA from the fetus (which is placentally derived). The percentage of DNA in the maternal blood sample that comes from the placenta is known as the fetal fraction (FF). Factors that impact FF include gestational age, multiple gestations, maternal BMI, fetal aneuploidy, maternal disease, and medication.
Illumina’s NIPT performance at lower fetal fraction
Illumina’s VeriSeq NIPT Solution v2 approach allows samples with low fetal fraction to be reported, reducing NIPT failures. This method uses paired-end sequencing to measure fragment length, adding to FF estimation.
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