Understanding non-invasive prenatal testing (NIPT) results requires careful consideration. NIPT is a screening test that analyzes cell-free DNA in maternal blood to assess the risk of certain chromosomal abnormalities in a fetus. Interpretation focuses on understanding reported risk scores, which indicate the likelihood of specific conditions like Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and Patau syndrome (Trisomy 13). Results are typically presented as either a “low risk” or “high risk” assessment, though some reports may offer a numerical probability or a “no call” result requiring further investigation. For example, a report stating “low risk for Trisomy 21” suggests a significantly decreased chance of the fetus being affected by Down syndrome.
The importance of accurately interpreting the assessment stems from its influence on subsequent prenatal care decisions. A low-risk result can provide reassurance to expectant parents, potentially reducing the need for invasive diagnostic procedures. A high-risk result, conversely, warrants further investigation, such as chorionic villus sampling (CVS) or amniocentesis, to confirm the diagnosis. The introduction of NIPT has significantly decreased the number of invasive procedures performed while improving the detection rate of common chromosomal abnormalities. Historically, prenatal screening relied on maternal age and biochemical markers, which had lower detection rates and higher false-positive rates compared to modern NIPT methods.
