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• Self-sampling for HPV-detection: factors affecting sensitivity need to be considered
  Veronique Verhoeven
  Published on: 13 May 2016

• Published on: 13 May 2016

  Self-sampling for HPV-detection: factors affecting sensitivity need to be considered

  • Veronique Verhoeven, researcher
  • Other Contributors:
    • Marc Baay, Paul Van Royen, Jan B. Vermorken

  Dear Editor,

  Ogilvie et al. have published a well-designed meta-analysis of the diagnostic accuracy of self collected vaginal specimens for human papillomavirus (HPV) detection, in which they conclude that self-sampling may be an appropriate alternative for low resource settings or in patients reluctant to undergo pelvic examinations.[1] However, we have a number of remarks on the pooled sensitivities and specificit...

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  Dear Editor,

  Ogilvie et al. have published a well-designed meta-analysis of the diagnostic accuracy of self collected vaginal specimens for human papillomavirus (HPV) detection, in which they conclude that self-sampling may be an appropriate alternative for low resource settings or in patients reluctant to undergo pelvic examinations.[1] However, we have a number of remarks on the pooled sensitivities and specificities they present.

  First, it is not an optimal strategy to choose clinician-collected vaginal specimens as the reference standard to compare self-sampled specimens to, since it is the concordance of self-sampling with presence of HPV-DNA in the cervical epithelium which determines the usefulness of vaginal sampling as a screening test for cervical cancer. It would have been more accurate to assess sensitivity and specificity compared to a cervical specimen, sampled in a standardized way by a clinician, as the golden standard.

  Second, if guidelines for self-sampling are made, the accuracy of HPV- detection in a single sample must be maximized. A number of factors that may affect detection of HPV have been suggested in literature and are currently under further investigation. Short term fluctuations in prevalence of HPV within the menstrual cycle have been described.[2] Hormonal fluctuations within a menstrual cycle may affect HPV detection since progesterone causes deeper exfoliation of cervical and vaginal epithelium, where HPV assemblance takes place, whereas estrogens promote exfoliation of only the superficial layers, which does not allow maturation of the parabasal cells that is required for HPV assembly and release.[3,4]

  Furthermore, vaginal penetration by coitus [4] could mechanically remove HPV infected cells, as could hygienic tampon use or vaginal douching. In case of unprotected intercourse, false positive tests could result from detecting HPV-DNA from the male partner.[4] Few empirical data confirm the latter theoretical considerations so far. It has been insufficiently examined to what extent vaginal lubricants, spermicidal cream or other intimate products, or even antibiotics, which affect the vaginal micro-climate or pH, could have an impact on HPV detection.

  Finally, we observed in a small study that recent vaginal infections resulted in discordance of HPV detection between vaginal and cervical samples.[5] Indeed, it is conceivable that a vaginal infection speeds up the discharge of exfoliated (HPV-infected) cervical cells, thereby shortening the period of time these cells are present in the vagina. It is clear that at least some of these factors will affect sensitivity and/or specificity of vaginal self-sampling, and it is advisable to establish their effect on accuracy of vaginal sampling before practice recommendations are made.

  References

  1. Ogilvie GS, Patrick DM, Schulzer M, Sellors JW, et al. Diagnostic accuracy of self collected vaginal specimens for human papillomavirus compared to clinician collected human papillomavirus specimens: a meta- analysis. Sex Transm Infect 2005;81:207-12.

  2. van Ham MA, Melchers WJ, Hanselaar AG, Bekkers RL, et al. Fluctuations in prevalence of cervical human papillomavirus in women frequently sampled during a single menstrual cycle. Br J Cancer 2002;87:373-6.

  3. Ferenczy A, Wright TC Jr. Anatomy and histology of the cervix. In: Kurman R, ed. Blaustein’s Pathology of the female genital tract. 5th ed. New York, NY: Springer; 2002.

  4. Harper DM, Longacre MR, Noll WW, Belloni DR, Cole BF. Factors affecting the detection rate of human papillomavirus. Ann Fam Med. 2003;1:221-7.

  5. Baay M, Verhoeven V, Wouters K, Lardon F, et al. The prevalence of the human papillomavirus in cervix and vagina in low-risk and high-risk populations. Scand J Infect Dis 2004; 36:456-9.

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  Conflict of Interest:
  None declared.

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