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Amniotic Fluid, Chromosome Analysis; Chromosome Analysis, Amniotic Fluid; Karyotype, Amniotic Fluid; Prenatal Chromosomes, Amniotic Fluid; Fetal Aneuploidy; Fetal Chromosome Analysis; DNA Screening for Fetal Aneuploidy
Chromosome Analysis, Amniotic Fluid (CHRAF)
Chromosome Analysis, Amniotic Fluid
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
-Improper syringes or transport vessels may be unsuitable to amniotic cells. Amniotic fluid should not be exposed to the syringe plunger tip for longer than a few seconds and fluid should be transferred to a transport (centrifuge) tube as soon as possible following collection.
-Transport time should not exceed 2 days.
-A bloody specimen may interfere with attempts to culture cells and contamination by maternal cells may cause interpretive problems.
-Inadequate amount of fluid may not permit adequate analysis.
-Improper packaging may result in broken, leaky, and contaminated specimen during transport.
-Exposure of the specimen to temperature extremes (freezing or >30 degrees C) may kill cells and severely interferes with attempts to culture cells.
Mayo Clinic Laboratories
Chromosome analysis for prenatal diagnosis is appropriate in pregnancies with abnormal maternal screening, advanced maternal age, and features suggestive of or concerns for aneuploidy syndromes, including Down syndrome, Turner syndrome, Klinefelter syndrome, trisomy 13 syndrome, and trisomy 18 syndrome.
Chromosomal abnormalities are the cause of a wide range of disorders associated with birth defects and congenital diseases. Many of these disorders can be diagnosed prenatally by analysis of amniocytes. This method permits diagnosis of chromosome abnormalities during the second trimester of pregnancy or later.
A chromosomal microarray (CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling) is recommended, rather than chromosomal analysis, to detect clinically relevant gains or losses of chromosomal material in pregnancies with 1 or more major structural abnormalities. Chromosomal microarray can also be considered, rather than chromosome analysis, for patients undergoing invasive prenatal diagnostic testing with a structurally normal fetus.