In this study of young women who performed a simple POC test for trichomoniasis, we found that the scale we developed to measure acceptability of self-testing for trichomoniasis demonstrated good internal consistency and reliability. The subscales were consistent with the same four-factor structure described for acceptability of self-sampling for HPV.27
At baseline, overall acceptability did not differ for self and clinician testing. However, analysis of acceptability subscale scores showed that participants perceived self-testing for trichomoniasis as more comfortable than clinician testing, were less confident of their ability to collect/perform the test, and trusted the results less than clinician testing. Two other studies have assessed acceptability of self-testing for STIs.28,29
Adult women in South Africa were randomised to home testing versus clinic-based testing for STIs. Both groups performed a POC test for trichomoniasis similar to the one we describe. Acceptability was assessed after testing using four items that measured two subscales: comfort (pain with self-sampling) and confidence (easy to collect the sample, follow test instructions, and read the results). Over 90% responded positively to confidence questions, and only 15% reported pain with sampling. Acceptability was not compared with clinician sampling.28
One study of self-testing for HIV among adult men in China described acceptability as confidence in performing the test (easy to understand and use) and perceived effects of testing (would recommend to others). After performing the self-test, over 90% endorsed self-testing as easy to use and would recommend, but self-testing was not compared with clinician testing.29
Differences in measuring and reporting acceptability in these studies highlight the need for well-defined scales in order to compare results across studies.
We found several similarities to studies evaluating acceptability of self-sampling. Kahn et al
found that adolescent women rated clinician sampling to detect HPV higher than self-sampling for confidence, perceived effects and trust of results.27
Another group compared acceptability of a self-obtained swab for HPV testing with clinician testing using a six-item scale that measured embarrassment, discomfort, anxiety, relaxation, unpleasantness and confidence. Women were more confident in clinician testing, but it was also rated as more embarrassing, unpleasant and anxiety-provoking, and less comfortable and relaxing than self-sampling.30
In a third study, acceptability of self-sampling for chlamydia/gonorrhoea was defined as five items encompassing preferences (provider testing vs self-swab), unpleasantness and confidence in ability to perform the test (instructions were clear, easy to get the swab). The majority (>90%) endorsed high satisfaction with self-sampling for each item.31
These results are consistent with our findings and speak to the validity and generalisability of the constructs `comfort' and `confidence' which we describe. However, few other studies besides ours have measured the construct `trust in test results'.
In addition to measuring baseline acceptability in more depth than others, ours is one of few studies to compare clinician- and self-testing subscales with each other over time. This approach revealed important details that would have been missed by measuring total acceptability. Although both confidence and trust of self-test results were initially lower than clinician results, scores improved over time until they were equivalent to those for clinician-test results. After discussion of test results, women whose test results were concordant with clinicians' results had higher trust scores. In contrast, Kahn et al
found an increase in confidence, but not in trust, of self-sampling results over time; however, HPV test results were not available at the visit.27
We believe that by using a POC test we were able to give immediate feedback and positive reinforcement when the self-test was performed and interpreted correctly, which influenced the participant's trust and confidence around self-testing.
While acceptability of self-testing increased over time, there was no change in willingness to test at home. Similarly, others reported no change in HPV testing preferences over time (about 62% preferred clinician testing at each time point).27
In contrast, others have found that successful participant experience with self-testing influenced preferences: women randomised to home testing were more likely than those randomised to clinic testing to prefer self-sampling and self-testing at home over clinic.28
It is possible that the experience of testing oneself at home, without supervision, confers a sense of confidence and empowerment that self-testing in clinic does not.
Similar to others,27
we found that comfort of clinician testing was initially rated as lower than self-testing, but increased over time, suggesting that the pelvic examination was less uncomfortable than expected. Across many studies, women acknowledge that self-testing and self-sampling is more comfortable than clinician testing regardless of participant characteristics, settings and type of test.27,28,30
The main factor that predicted acceptability was an open attitude towards self-testing–that is, women who were willing to test themselves at home endorsed higher overall acceptability, confidence, comfort and perceived effects of testing. Experience with products (eg, tampons) that require genital touching was associated with increased comfort subscales, congruent with our clinical experience. Others have demonstrated that comfort with genital touching predicted acceptability of a vaginal contraceptive ring.32
Self-testing is a novel strategy that could remove barriers that adolescents face in getting screened for STIs. Women would be expected to choose self-testing for trichomoniasis and other STIs for the same reasons that they choose home pregnancy testing: improved privacy, wider access, faster results, and lower cost than requesting testing from a clinician. Self-testing for common STIs (such as chlamydia, gonorrhoea and trichomoniasis) would be ideal, but thus far only a reliable POC test for trichomoniasis is available. Still, a positive POC test for trichomoniasis would be useful, as it could serve as an entry point for a wider STI screen. For example, a positive test result for trichomoniasis could motivate adolescents to seek screening for other infections as well. Although home self-testing for STIs would eliminate clinician counselling and treatment of positive results that the adolescent would get during an in-person visit with testing, a similar situation occurs with home pregnancy testing. The package inserts for over-the-counter home pregnancy tests contain the advice to speak with a clinician regarding positive results. Further, the package insert for the already marketed home pH test advises women to seek evaluation from their clinician for further testing and diagnosis. Similarly, if any POC STI test was available for home use, the package insert would advise women to confirm their results with a clinician and to seek evaluation for other concomitant infections.
Strengths of this study are its large sample size and use of a validated measure for assessing acceptability of trichomoniasis self and clinician testing. A limitation to our study is that all women agreed to self-testing as a condition of study participation; thus, they may represent a group that has higher self-testing acceptability than others. Alternatively, since we recruited women from clinical care settings, participants may have been biased to prefer clinician testing over self-testing. We did not measure perceived severity of the disease, a factor that might influence acceptability. We did not measure the impact of cost of testing on acceptability. Women in Brazil report that they would pay up to $4 for an STI self-test kit,33
and currently home STI testing kits are advertised online at $40–$250. Also, we were unable to assess whether higher acceptability and theoretical willingness to test oneself at home translated into actual self-testing behaviour. Future studies should evaluate acceptability in non-clinical samples and compare reported acceptability with measurable outcomes such as STI testing patterns and disease rates.
In this first study to comprehensively evaluate the acceptability of self-testing for trichomoniasis, our results suggest that women initially perceive self-testing as more comfortable but less reliable than clinician testing, and many lack confidence in their ability to perform a POC test and interpret the results. As self-testing for STIs becomes more widely available, women may need to be reassured about the accuracy of these tests. Allowing a woman to try a POC STI test in the office and review her results with the clinician was a simple, hands-on strategy that increased acceptability and trust of self-test results regardless of her baseline preferences or other sociodemographic factors. This `skills-based' approach to patient education may be invaluable for enhancing the use of any POC STI tests by adolescents, should they become available in the future.