Diagnosis and Testing
How do I get tested for Down Syndrome?
Down syndrome can be diagnosed by chromosome analysis before a baby is born (prenatally) or after a baby is born (postnatally). The most common type of chromosome analysis used to diagnose Down syndrome is known as a karyotype, which is essentially an organized image of the chromosomes within a cell obtained by microscopic evaluation.
A karyotype is most often obtained prenatally on a sample of cells from amniotic fluid (via a procedure known as amniocentesis) or placental tissue known as chorionic villi (via chorionic villus sampling). There are several prenatal screenings (e.g. blood tests on the mother and ultrasound examinations) that can identify pregnancies at increased risk for Down syndrome, but these are not diagnostic and should not be relied on as final test results.
If a karyotype is performed on an individual postnatally, it is most often done on a blood sample.
If you wish to obtain more information about the specific testing used to diagnose Down syndrome, consider making an appointment with a genetic counselor. To find a local genetic counselor, use the Find a Genetic Counselor search tool on the National Society of Genetic Counselors' website.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/down-syndrome/diagnosis-testing/17525 • DATE UPDATED: 2016-06-22