Rapid DNA extraction methods to facilitate laboratory workflow in Alpha-1 Antitrypsin Deficiency detection

<bold>Introduction:</bold> Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder that may result in lung and/or liver disease. Most patients with AATD are undiagnosed. AATD screening can be performed on saliva collected as buccal swabs, a minimally invasive technique. <bold>Aim:</bold> Our aim was to optimise and validate three rapid DNA extraction methods from saliva using commercial reagents to simplify sample preparation procedures prior to AATD genotyping. <bold>Methods:</bold> Three rapid DNA extraction methods were validated for saliva collected with ORAcollect swabs (DNAgenotek): Lysis&Neutralization (Merck), Extracta DNA Prep for PCR (QuantaBio) and KAPA Express extract (KAPABiosystems), as per manufacturer´s instructions but optimized for saliva samples. DNA was extracted from selected (Z/Z, M/Z, S/S, M/S and S/Z) and random donors. DNA samples extracted with the 3 methods were processed with the A1AT Genotyping Test (Progenika Biopharma, A Grifols Company), a PCR and hybridization-based in vitro diagnostic assay using Luminex® technology. <bold>Results:</bold> The rapid DNA extraction methods substantially minimized hands-on-time, requiring just 1-2 reagent addition steps and 15-minute incubation in a thermocycler. Despite yielding non-purified DNA, all methods gave 100% valid and correct results with the A1AT Genotyping Test. <bold>Conclusions:</bold> The three rapid DNA extraction procedures validated for saliva samples collected in buccal swabs proved to be simple and yielded robust performance in combination with the A1AT Genotyping Test assay. The methods allow manual or automated high-throughput preparation of DNA samples and have been successfully implemented in Grifols Clinical Diagnostic Laboratories.