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