FlashFISH: Same Day Prenatal Diagnosis of Common Chromosomal Aneuploidies

Fluorescence in situ hybridization (FISH) and quantitative fluorescence (QF)-PCR are rapid molecular methods that test for common chromosomal aneuploidies in prenatal diagnosis. While cytogenetic analysis requires approximately 7–14 days before fetal karyotypes are available, these molecular methods release results of sex chromosome aneuploidies, Down syndrome, Edward’s syndrome, and Patau’s syndrome within 24–48 h of fetal sampling, alleviating parental anxiety. However, specific diagnosis or exclusion of aneuploidy should be available within the same day of amniocentesis. We developed “Flash FISH,” a low cost FISH method that allows accurate results to be reported within 2 h of fetal sampling. Here, we report our experience of using Flash FISH in prenatal diagnosis, and we illustrate in detail the protocols used for the purpose in our laboratory.