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

Cody A Ruiz,Morgan E Chaney,Anthony J Tosi

doi:10.1016/j.mex.2018.01.006

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.

Highlights

There remains a dearth of independent investigation into the DNA yield acquired from various medical and non-medical swab types despite the stark cost difference between the two
This led us to test the hypothesis that medical-grade buccal swabs on average will yield more DNA than standard cotton swabs (Q-tipsJ, Unilever, United States)
When using the standard cotton swabs (Q-tipsJ; n = 8) which have two cottontipped ends per swab, buccal cells were collected from both cheeks – one end of the swab for each side of the mouth – and the two swab ends were combined as a single sample

Summary

Introduction

The use of buccal swabs is becoming a common method for collecting human and nonhuman DNA samples because it is rapid, non-invasive, and has been shown to produce a sufficient yield for a variety of genetic assays [1,2,3]. There remains a dearth of independent investigation into the DNA yield acquired from various medical and non-medical swab types despite the stark cost difference between the two. This led us to test the hypothesis that medical-grade buccal swabs on average will yield more DNA than standard cotton swabs (Q-tipsJ, Unilever, United States).

Results

Conclusion