A pilot study to compare dry cervical sample collection with standard practice of wet cervical samples for human...

For human papillomavirus (HPV) DNA detection, specimen collection and transportation using a dry swab without transport medium has advantages, in various situations, over liquid media.

In this pilot study we evaluated whether a dry cervical sample taken with a flocked swab (dry sample) is a valid alternative for HPV DNA testing compared with the standard practice of a wet sample taken with a cyto-broom placed directly into liquid media (wet sample).

Women attending the dysplasia clinic at the Royal Women's Hospital, Melbourne Australia between November 2013 and February 2014 were enrolled. During colposcopic examination, a practitioner collected wet and dry cervical samples, with the order of collection randomised. In the laboratory both samples were left for a week before being tested for 14 high-risk HPV types using the Roche Cobas 4800 test.

Overall, 209 had valid HPV results from both samples. The observed agreement for HPV detection between wet and dry samples was 92.8% and kappa was 0.85 (95% confidence interval (95% CI): 0.78-0.92). There was no statistical difference in the percent HPV positive for each sample (p = 0.30). HPV testing of the dry sample had an 88.5% (95% CI: 79.9-94.3%) sensitivity for HPV detected using the wet specimen. For the HPV results categorized hierarchically, there was 92.8% overall agreement and a kappa of 0.87 (95% CI = 0.80-0.93) for the paired results.

Using dry flocked swabs to collect cervical cells is a valid alternative to collecting wet samples for HPV DNA testing using a PCR based test.