Non-professionals using professional rapid HIV testing reagents for HIVST may have problems. The stages of sample collection, testing and result interpretation[8-10] may affect the test accuracy. In this study, MSM participants were asked to do HIVST using rapid HIV testing kits without any assistance or guidance. The results showed that MSM can better complete urine HIVST with the operation accuracy rate is 82.1%, which is consistent with the research of Roger B. Peck et al[11]. However, the operating errors were common in OMT and blood HIVST, the operating accuracy rate were only 11.5% and 23.5%, respectively. Studies have shown that the high error rate in OMT HIVST is due to the complex OMT collection and test process, the too numerous descriptions in the instructions to users' failure to read or understand carefully[12]. And the most common error in blood HIVST was "reading results after 30 minutes", perhaps due to participants were anxious to know their infection status and immediately interpreted the results when the test strip display. This is different from the study of Mohammed Majam and Smith P[13,14], which operational errors mainly occurred in the blood collection and sampling process. In addition, during the urine HIVST, the most mistakes were "adding 3 drops of urine to the sample area of the test card", which may be due to some participants did not read the instructions carefully. Therefore, this study suggest that the clear, understandable and interesting instructions should be used to improve the feasibility of non-professionals HIVST[11].
Results analog picture discriminant evaluation showed that the strong reactive and non-reactive results with the highest interpretation accuracy, while the weakly reactive results with low interpretation accuracy, which was consistent with the relevant research results[9,11,12,15]. Especially, the more complex invalid results of "no quality control line /T line, with test line /C line" is far lower than the invalid results of "no quality control line /T line, no test line /C line". In this regard, relevant studies have shown that use different symbols for test lines and control lines could increase the results interpretation accuracy[11]. Therefore, it is suggested that clear, simple and easy to distinguish symbols can improve the results interpretation accuracy.
According to the evaluation results of participants' understanding the cautions, operation processes and results interpretation in the reagent instructions, more than half questions with less than 70% comprehension accuracy rate, which was consistent with the relevant domestic studies[12]. However, the study of Gresenguet[15] showed most people could correctly understand the instruction information. It may be the reagent instructions used in this study were full of words and contained technical terms, which led to participants' inability to accurately identify and effectively understand while simple and understandable colloquial descriptions of instructions were used in Gresenguet's study. More important, the low understanding accuracy of "HIV infection cannot be ruled out if the test result is negative, and HIV infection cannot be confirmed if the test result is positive" will affect the users' subsequent solutions choice. Remind us again, using easy to understand instructions is more conducive to non-professional users to accurately understand the key information.
This study found when the HIVST results were reactive more than 80% people choose to confirm by medical institution, when the results were nonreactive most people choose to regular retest, and when the results were invalid more than 80% people choose to test again. It is suggested that HIVST can help to find more HIV infected people, to some extent[12,16].
If provided some help to HIV self-testers such as simple instructions and video tutorials, the HIVST results can be highly consistent with professional medical and health workers [17]. Studies showed the OMT HIVST accuracy is 97.0%[18], 92.5% [12], and 83.3% [19]. In this study, the HIVST accuracy of urine, OMT, and blood were 96.9% (255/263), 91.8% (56/61) and 100% (17/17). There was no factors affecting the HIVST accuracy by evaluation results analysis, the possible reasons were the HIV antibody content different between urine, OMT, and blood which due to the interfering substances of urine and OMT, and also may be because of the small sample size in this study.
Studies have shown that the urine of HIV-1 infections is unlikely contain infectious HIV-1, the risk of transmission of HIV-1 by urine is low to nonexistent[20]. And the urine sampling is non-invasive and painless which can improve testers to choose and acceptance. In this study, we found if HIVST was conducted again, 54.1% MSM tended to choose blood test reagents, 15.8% to choose blood and urine test reagents, 14.4% choose urine test reagents, and the reasons were people believes blood test is more accurate but urine test is more convenient. It is consistent with the study results of Witzel et al. [21] and Lippman et al. [22], which also showed that HIV blood test in MSM was more acceptable because of MSM believe it more accurate. However, the research of Marley et al. [81] showed 72.8% MSMs accepted OMT test because convenience, painless, easy to collect samples and test [23], while only 15.1% MSMs considered choosing OMT test in this study because the urine test also has the characteristics of above and and HIV antibodies in urine samples is very stable, can directly test [24]. So the MSMs be inclined to choose more convenient urine and more accurate blood.
In conclusion, this study for the first time to evaluated the understanding ability of key information in manual, the interpretation ability of simulation results, and the operation ability of HIVST, and the preference for urine, blood and OMT, when unprofessional MSMs used professional rapid test kits for HIVST lays a scientific theoretical basis for further carring out HIVST in China.