Evaluation of Transported Dry and Wet Cervical Exfoliated Samples for Detection of Human Papillomavirus Infection

Abstract

We determined the feasibility of human papillomavirus (HPV) detection in cervical exfoliated cells collected as dry swab samples. Both dry cervical swab and specimen transport medium (STM) cervical swab samples were collected from 135 patients attending either colposcopy or women's clinics in Guayaquil, Ecuador, who had a cytology diagnosis within 6 months. HPV was detected by dot blot hybridization and genotyped by the liquid bead microarray assay (LBMA). Overall, 23.1% of dry samples were positive for any high-risk HPV types, and 24.6% of STM samples were positive for any high-risk HPV types. Of 125 paired samples, the type-specific high-risk HPV proportion positive agreement was 60.7% (kappa, 0.69; 95% confidence interval [CI], 0.53 to 0.82). Of six women with cytological evidence of invasive cervical cancer, high-risk HPV DNA was detected in three of their STM samples and in five of their dry samples. Dry samples were more likely to be insufficient for HPV testing than STM samples. Consistent with this observation, the amount of genomic DNA quantitated with the ␤-actin gene was almost 20 times lower in dry samples than in STM samples when detected by the real-time TaqMan assay; however, HPV DNA viral loads in dry samples were only 1.6 times lower than those in matched STM samples. We concluded that exfoliated cervical cells could be collected as dry swab samples for HPV detection.Human papillomavirus (HPV) infection causes warts and various cancerous and precancerous lesions in men and women. It has been established that high-risk HPV infection is the etiological agent of cervical cancer, which affects almost half a million women worldwide and has a 50% mortality rate (12,18). In developed countries, cervical cancer control relies on routine cytology screening to detect and treat cervical cancer precursor lesions, and HPV detection has been used for the management of women with equivocal cytology results (1,4,14). In resource-poor settings where cytology-based screening is difficult to implement, HPV detection has been proposed as the alternative primary screening test for cervical cancer (4, 17).Currently, HPV detection is performed on cervical samples collected in liquid medium by a trained clinician, which is often impractical or unavailable in remote areas and developing countries. Several approaches have been proposed to simplify the sample collection process for HPV detection. For example, HPV detection in self-collected vaginal swab samples has been proposed as a method that would eliminate the need for clinical visits, and we have shown that HPV detected in selfcollected vaginal swab samples stored in specimen transport medium (STM) had sensitivity and specificity similar to those of clinician-collected cervical swab samples stored in STM for detecting cervical neoplasia (16). Currently, cervical exfoliated cells are collected either in phosphate-buffered saline (PBS), which is inexpensive but requires constant refrigeration, or in various liquid media, such as STM or Preservcyt, which preserve HPV D...

Evaluation of dry and wet transport of at-home self-collected vaginal swabs for human papillomavirus testing

“…Feng et al (2010) observed substantial agreement between high-risk HPV (for positive agreement k 0.61) cervical samples, collected from 135 women (mean age 38) attending colposcopy or women's clinics in Ecuador, that were transported dry and wet. Time between sample collection and HPV testing was longer in the study of Feng et al (2010) because samples were refrigerated for up to 6 months before they were shipped from Ecuador to Washington State for HPV testing. Differences in age, HPV prevalence and sampling site between Feng et al (2010) and the present study could also account for differences in observed agreement.…”

“…Infections detected in younger women may be more likely to reflect newer HPV infections with higher viral loads (Winer et al, 2007) and because higher viral loads increase the likelihood of detecting the virus in a sample (Winer et al, 2007), agreement between samples could be enhanced compared to infections with lower viral loads. Feng et al (2010) compared clinician-collected cervical samples, while our study compared self-collected vaginal samples. We previously demonstrated that greater numbers of HPV infections were detected in paired vulvovaginal versus cervical samples, possibly due to the larger surface area of the vagina compared to the cervix (Winer et al, 2003(Winer et al, , 2007.…”

“…Time between sample collection and HPV testing was longer in the study of Feng et al (2010) because samples were refrigerated for up to 6 months before they were shipped from Ecuador to Washington State for HPV testing. Differences in age, HPV prevalence and sampling site between Feng et al (2010) and the present study could also account for differences in observed agreement. Our study population was younger (mean age 23) and the prevalence of high-risk HPV was higher (40.1 vs 23.1 %).…”

“…There is some concern that shipped samples have the potential for loss of HPV DNA through sample degradation (Baay et al, 2009;Feng et al, 2010) and that this may be more pronounced in samples transported in a dry state (Feng et al, 2010).…”

“…On: Fri, 11 May 2018 05:45:26 collection and transportation methods for detecting Neisseria gonorrhoeae and Chlamydia trachomatis (Gaydos et al, 2002) and HPV (Shah et al, 2001;Feng et al, 2010;Kailash et al, 2002;Shukla et al, 2010). There is some concern that shipped samples have the potential for loss of HPV DNA through sample degradation (Baay et al, 2009;Feng et al, 2010) and that this may be more pronounced in samples transported in a dry state (Feng et al, 2010).…”