Is self-collection of testing samples an effective strategy for sexually transmitted infection testing?

Prevention in Focus PiF 2020 Spring

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Sexually transmitted infection (STI) rates are on the rise in Canada. Between 2008 and 2017 infection rates increased by 39% for chlamydia, 109% for gonorrhea and 167% for syphillis.1,2 Although STI testing is essential to identifying new infections, a 2018 survey of Canadians found that 50% of respondents had never been tested for an STI.3 Innovative strategies are needed to address barriers to testing, which include STI-related stigma, difficulty accessing testing services and concerns about privacy and confidentiality.4 One potential strategy is the self-collection of samples for testing. This article summarizes a systematic review examining the impact of self-collection of samples on STI testing outcomes.5

What is the self-collection of STI testing samples?

Self-collection, or self-sampling, is a method in which individuals take the specimen(s) needed for testing by themselves, and the specimens are then sent to a laboratory for testing.6 Self-collection may occur in a healthcare, home or community setting. It may involve taking urine samples or swabs of the rectum, vagina, urethra or throat, depending on the STI. Research has demonstrated that testing on self-collected samples is as accurate as testing on samples collected by healthcare providers and that self-collection is acceptable to those being tested.7,8

An example of STI self-collection services in Canada is GetCheckedOnline, an online STI testing service from the BC Centre for Disease Control that includes self-collection for chlamydia and gonorrhea testing.9

What kind of research does the systematic review include?

The systematic review includes research on the impact of self-collection on STI testing outcomes. The review was conducted to inform World Health Organization guidelines on self-collection for STI testing and to determine if self-collection should be recommended as an additional strategy to complement existing testing recommendations.

Eleven studies were included in the review, including five randomized controlled trials and six observational studies. A study was included if it compared self-collection with collection by a healthcare provider, for testing of chlamydia, gonorrhea, syphilis or trichomoniasis, or if it compared self-collection with no STI testing. Studies needed to measure the impact of self-collection on one or more of the following outcomes:

  • uptake of STI testing
  • frequency of STI testing
  • social harms or adverse events related to STI testing
  • proportion of people who tested positive for an STI (case finding)
  • linkage to treatment and care among people who tested positive for an STI
  • sexual risk behaviour

Characteristics of the studies included in the review were as follows:

  • published between 1998 and 2018
  • represented approximately 202,000 participants
  • took place in the United States (six studies), Denmark (three studies) or Australia (two studies)
  • tested for chlamydia, gonorrhea and/or trichomoniasis (no studies tested for syphilis)
  • used self-collection in clinical (three studies) or home-based (eight studies) settings
  • employed urine samples; vaginal flush using saline; or throat (pharyngeal), rectal, urethral or vaginal swabs for self-collection
  • focused on a range of populations including the general population, men who have sex with men, people with HIV, youth, and people who use injection drugs

Is self-collection of testing samples an effective strategy for STI testing?

The review found that the evidence supports the use of self-collection as a strategy to facilitate STI testing. This conclusion was reached by examining the impact of self-collection of samples on the uptake of STI testing and the proportion of people who tested positive for an STI. The review also sought studies that examined the impact of self-collection on frequency of STI testing, social harms or adverse events related to STI testing, linkage to treatment and care among people who tested positive for an STI or sexual risk behavior, but no studies that looked at these outcomes could be located.

Uptake of STI testing

Eight studies examined the impact of self-collection on the uptake of STI testing, including the five randomized controlled trials and three of the observational studies.

A meta-analysis based on the results of the five randomized controlled trials found that participants were three times more likely to get tested for an STI with self-collection of samples than with collection by healthcare providers. This association was stronger for males who self-test (seven times more likely) than for females who self-test (three times more likely). The observational studies also found a positive association between self-collection and uptake of testing.

Proportion of people who test positive for an STI (case finding)

Nine studies examined the impact of self-collection on the proportion of people who test positive for an STI, that is, the likelihood of finding positive tests. Four studies were randomized controlled trials and five were observational studies.

A meta-analysis of the randomized controlled trials found that self-collection was less likely to result in a positive test result than collection by healthcare providers among those who were tested. The observational studies found no difference in case finding between the two collection methods.

What are the implications of the review for service providers?

The evidence from this systematic review supports the use of self-collection of samples as a strategy to facilitate STI testing. This review examined the impact of self-collection of testing samples on STI testing outcomes by comparing self-collection with collection by healthcare providers. It found that self-collection of samples increased the uptake of STI testing, with a greater impact on males who self-test than females who self-test.

When considering this review, it is important to remember that:

  • The review is based on 11 studies and it found evidence for only two of the six outcomes of interest (i.e., uptake of testing and positivity rates) and for only the testing of chlamydia, gonorrhea and/or trichomoniasis (no studies tested for syphilis).
  • Future research may provide evidence for additional outcomes such as the impact of self-collection on testing frequency.
  • The review included a broad range of populations and considered uptake of testing by gender but did not compare outcomes using other demographic or social characteristics. Further research may help determine if there are additional self-collection differences among populations.

What is a systematic review?

Systematic reviews are important tools for informing evidence-based programming. A systematic review is a critical summary of the available evidence on a specific topic. It uses a rigorous process to identify all the studies related to a specific research question. Relevant studies can then be assessed for quality and their results summarized to identify and present key findings and limitations. If studies within a systematic review contain numerical data, these data can be combined in strategic ways to calculate summary (“pooled”) estimates. Combining data to produce pooled estimates can provide a better overall picture of the topic being studied. The process of pooling estimates from different studies is referred to as a meta-analysis.

 

References

  1. Public Health Agency of Canada. Notifiable diseases online. Ottawa: Public Health Agency of Canada; 2019. Available from: http://diseases.canada.ca/notifiable/
  2. Government of Canada. Infectious syphilis cases reported in Canada 2009-2018. Canadian Communicable Disease Report; 2019;45-11, November 7. Available from: https://www.canada.ca/en/public-health/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2019-45/issue-11-november-7-2019/article-5-infectious-syphilis-canada-2009-2018.html
  3. EKOS Research Associates Inc. Canadians’ awareness, knowledge and attitudes related to sexually transmitted and blood-borne infections: 2018 findings report. Ottawa: Public Health Agency of Canada; 2018. Available from: http://epe.lac-bac.gc.ca/100/200/301/pwgsc-tpsgc/por-ef/public_health_agency_canada/2018/056-17-e/report.pdf
  4. Public Health Agency of Canada. Reducing the health impact of sexually transmitted and blood-borne infections in Canada by 2030: a pan-Canadian STBBI framework for action. Ottawa: Public Health Agency of Canada; 2018. Available from: https://www.canada.ca/content/dam/phac-aspc/documents/services/infectious-diseases/sexual-health-sexually-transmitted-infections/reports-publications/sexually-transmitted-blood-borne-infections-action-framework/sexually-transmitted-blood-borne-infections-action-framework.pdf
  5. Ogale Y, Yeh PT, Kennedy CE, et al. Self-collection of samples as an additional approach to deliver testing services for sexually transmitted infections: a systematic review and meta-analysis. BMJ Global Health. 2019;4(2):e001349. Available from: https://gh.bmj.com/content/4/2/e001349
  6. World Health Organization. WHO consolidated guideline on self-care interventions for health: sexual and reproductive health and rights. Geneva: World Health Organization; 2019. Available from: https://apps.who.int/iris/bitstream/handle/10665/325480/9789241550550-eng.pdf?ua=1
  7. Paudyal P, Llewellyn C, Lau J, et al. Obtaining self-samples to diagnose curable sexually transmitted infections: a systematic review of patients’ experiences. PLOS ONE. 2015 Apr 24;10(4):e0124310. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0124310
  8. Yared N, Horvath K, Fashanu O, et al. Optimizing screening for sexually transmitted infections in men using self-collected swabs: a systematic review. Sexually Transmitted Diseases. 2018;45(5):294–300. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5889342/
  9. Gilbert M, Haag D, Hottes TS, et al. Get checked… where? The development of a comprehensive, integrated Internet-based testing program for sexually transmitted and blood-borne infections in British Columbia, Canada. JMIR Research Protocols. 2016;5(3):e186. Available online: https://www.researchprotocols.org/2016/3/e186/

 

About the author(s)

Erica Lee is CATIE’s manager, website content and evaluation. Since earning her Master of Information Studies, Erica has worked in the health library field, supporting the information needs of frontline service providers and service users. Before joining CATIE, Erica worked as the Librarian at the AIDS Committee of Toronto (ACT).