Description
The NIPT (Non-Invasive Prenatal Testing) is a highly accurate, safe blood test for pregnant women. It screens for common chromosomal conditions in the baby, such as Down syndrome, as early as 10 weeks into the pregnancy, without any risk of miscarriage.
Overview: During pregnancy, tiny fragments of the baby’s DNA (specifically, from the placenta) circulate in the mother’s bloodstream. NIPT analyzes this “cell-free DNA” (cfDNA) to look for missing or extra chromosomes in the fetus. Because it only requires a simple blood draw from the mother, it is completely non-invasive and carries zero risk to the baby.
What is measured: NIPT primarily screens for the most common chromosomal abnormalities (trisomies):
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Trisomy 21 (Down syndrome): Highly accurate detection.
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Trisomy 18 (Edwards syndrome): A condition causing severe developmental delays.
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Trisomy 13 (Patau syndrome): A condition causing severe intellectual disability and physical defects. Note: Depending on the specific NIPT panel chosen, it may also screen for sex chromosome aneuploidies (like Turner syndrome) or specific microdeletions.
Clinical Significance:
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High Accuracy: It is significantly more accurate than traditional maternal serum screenings (like the Double or Triple Marker tests), especially for Down syndrome, leading to fewer “false alarms.”
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Early Detection: It can be performed very early in the pregnancy, providing crucial information and peace of mind sooner.
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Avoiding Invasive Procedures: A low-risk NIPT result can often help women avoid invasive diagnostic procedures like amniocentesis or chorionic villus sampling (CVS), which carry a small risk of miscarriage. However, a “high risk” NIPT result must be confirmed with an invasive diagnostic test.
When is this test recommended?
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Timing: It can be performed any time after 10 weeks of gestation.
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Who should get it? While it is increasingly offered to all pregnant women, it is strongly recommended for:
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Women over the age of 35.
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Women who had an abnormal result on a previous ultrasound or routine screening test (like the Double Marker).
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Women with a prior pregnancy involving a chromosomal abnormality.
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Women with a family history of a specific genetic condition.
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Sample Requirements:
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Specimen: Whole Blood (Maternal).
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Container: Special Cell-Free DNA Collection Tubes (often Streck tubes, usually provided by the reference lab performing the specialized testing). Standard EDTA or SST tubes cannot be used.
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Preparation: No fasting is required.
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Crucial Data Required: Accurate gestational age (confirmed by ultrasound) is essential to ensure there is enough fetal DNA (fetal fraction) in the mother’s blood to run the test accurately.
