Use of buccal cells collected in mouthwash as a source of DNA for clinicaltesting

Context.-To maximize the participation rate in population genetic studies, alternatives to invasive whole blood collection are increasing. One such al ternative is buccal epithelial cell collection, which, in contrast to venip uncture and finger sticks, is painless. Buccal cells, if collected and puri fied efficiently, offer an acceptable source for DNA to be used in research and clinical applications. Objective.-To develop a noninvasive sampling method for collecting cells fo r routine DNA testing in a clinical laboratory setting. Design.-Five factors were used to evaluate several brands of mouthwash: (1) compatibility with the DNA purification chemistry, (2) DNA yield, (3) DNA quality, (4) DNA stability at room temperature, and (5) mouthwash taste. Ne xt an optimization study was undertaken to maximize DNA yield. Finally, a v alidation study was undertaken with the optimized protocol to test a panel of 14 donors for DNA yield and performance and to test for the stability of DNA held in mouthwash. Setting.-Industrial research and development laboratory. Results.-Of 5 mouthwashes tested, Scope brand mouthwash received the highes t overall ranking. The addition of proteinase K and glycogen to the protoco l significantly enhanced DNA yields, with a test panel (n = 14) giving a ra nge of 12 to 60 mug of DNA per donor. In a 4-week room temperature stabilit y study, the DNA in mouthwash samples was found to be stable for at least 2 weeks. Conclusion.-A clinically validated DNA purification chemistry was adapted t o a noninvasive specimen collection method. This method used a commercially available mouthwash, Scope, to collect buccal epithelial cells for the pre paration of high-quality DNA in high yield.