The Glass Slide Extraction System Snap Card Improves Non-Invasive Prenatal Genotyping in Pregnancies with Antibodies.

Background: Determination of fetal blood groups in maternal plasma samples critically depends on adequate pre-analytical steps for optimal amplification of fetal DNA. We compared the extraction of cell-free DNA by binding on a glass surface (BCSI SNAP™ Card) with an automated system based on bead technology (MagnaPure compact™).

Methods: Maternal blood samples from 281 pregnancies (7th-39th week of gestation) with known antibodies were evaluated in this study.

Capture of genomic DNA on glass microscope slides.

It is well known that DNA strands bind to silica surfaces in the presence of high concentrations of chaotropic salts. We developed simple methods to evaluate binding and recovery of DNA on flat glass microscope slides and compared their properties with commercially available silica "spin columns". Surprisingly, genomic DNA was recovered efficiently from untreated glass slides.