Medical-grade buccal swabs versus drugstore cotton swabs: No difference in DNA yield

Abstract

We tested three types of medical-grade buccal swabs against standard cotton swabs for differences in DNA yield. A panel of swab types – one drugstore (Q-tips®) and three medical-grade – was used for buccal cell collection from three different individuals. DNA was extracted from all swabs using a QIAcube robot; quantitation values were measured by an Alu-based qPCR assay; and differences were compared through a 2-way ANOVA. Our results demonstrate that cotton swabs recover as much DNA as medical-grade swabs, but at a tremendously lower cost. Cotton swabs also display the greatest consistency of DNA yield, as indicated by the lowest coefficient of variation among the four tested swab types. These findings suggest that the use of standard cotton swabs for buccal cell collection offers not only a significant cost savings, but a more consistent method compared to the use of medical-grade swabs. Method name: Buccal cell collection (swab-based), Keywords: Robotic extraction, Alu assay, DNA quantitation, Buccal swabs