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 "FlashFISH," 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 FlashFISH in prenatal diagnosis, and we illustrate in detail the protocols used for the purpose in our laboratory.