READIT: a novel technology used in the interrogation of nucleic acid sequences for single-nucleotide polymorphisms.

The ability to perform analyses for single-nucleotide polymorphisms (SNPs) has become routine in many molecular diagnostic laboratories. While various procedures and technologies are available to do so, we evaluated a novel technology for SNP analysis using the Factor V Leiden polymorphism as an example. The Factor V Leiden polymorphism G1691A is the most common genetic abnormality associated with hereditary thrombophilia. Current testing methods remain highly accurate yet their main disadvantage is gel-based detection. The READIT System (Promega Corp., Madison, WI) is a novel approach to SNP analysis that utilizes DNA polymerase-mediated pyrophosphorolysis to release dNTPs, which are converted to ATP and used in a luciferase detection reaction. We screened 280 DNA specimens, previously analyzed using the PCR/MnlI restriction digest assay, to evaluate READIT System capabilities along with the KingFisher robotic magnetic particle processor (ThermoLabsystems). Concordant results were obtained for 278/280 (99%) specimens. One discordant result was due to an equivocal relative light unit while the other was indeterminate. Both specimens gave correct results upon repeat analysis. The READIT System offers several advantages including: (1) rapid SNP analysis, (2) accuracy and precision, (3) cost effectiveness, (4) decreased turn-around times, (5) high throughput, and (6) excellent analysis software.