Noninvasive prenatal testing: benefits and limitations of the available tests

Background: The "gold standard" for prenatal diagnosis of aneuploidies is provided by the karyotype, which has high accuracy, but is dependent on invasive procedures, which generate risk of fetal loss. Different methodologies of development of noninvasive prenatal genetic tests (NIPT) for tracking aneuploidies, including sex chromosomes, have been made available for clinical use, for some microdeletions and triploids and for exclusion of paternity. These exams make use of three methodological tools: s-MPS, t-MPS and SNP. Genetic tests, despite the high cost, cover a broader range of clinical applications, have the advantage that can be performed early, with high accuracy, and low false positive rate. Type of article: Review. Setting: Department of Obstetrics and Gynecology, Science College of Santa Casa of sao Paulo (FSMSCSP), Sao Paulo-SP, Brazil. Design and methods: This study was a non-asystematic review, which searched PubMed / MEDLINE as a research source and aimed at the compilation of data, which allowed approaching the evolution, the technical and methodological advances of the available tests, the recognition of its benefits, limitations and future perspectives on NIPT. Conclusion: NIPT stand out for being applied earlier during the pregnancy with high accuracy and low false-positive rates, including a broad spectrum of clinical applications. The t-MPS is a recent technique used to evaluate aneuploidy that shows greater accuracy and lower cost than the s-MPS, but that is limited to being applied only to the most common aneuploidies. The SNP technique can search for more genetic conditions, besides presenting better accuracy.