Main Takeaways
- We should not include Mycoplasma genitalium.
- Urine samples alone are insufficient; swabs from additional sites are necessary.
- HIV and Syphilis are essential for meaningful screening.
- A positive test ≠ treatment necessary.
We reached out to Prof. Dr. med. Braun, a specialist in Infectiology, General Internal Medicine, and Pharmaceutical Medicine at Hirslanden Hospital, with a focus on sexually transmitted infections (STIs), in order to:
Prof. Dr. med. Braun emphasized the importance of clarifying the intended use of our test. For screening purposes, the test would be incomplete without including HIV and Syphilis. He advised against testing for Mycoplasma genitalium and cautioned that sequence selection must account for potential cross-reactivity between Neisseria gonorrhoeae and Neisseria meningitidis. He also noted that Trichomonas is usually tested only in symptomatic cases, not in general screening.
He emphasized that relying on urine samples alone is not enough, since roughly three-quarters of STIs occur extragenitally. To achieve reliable results, it is essential to test at the actual sites of exposure, which often means taking anal, genital, and pharyngeal swabs. For HIV and Syphilis, he explained, blood samples are required. In rare cases, Syphilis can even be detected earlier through a urethral swab, though this is the exception rather than the rule. He went on to clarify that HPV testing requires cervical or anal swabs rather than urine, as urine does not provide meaningful results. Similarly, while Chlamydia and Gonorrhea can be found in urine, they can be missed this way and are more reliably detected through additional pharyngeal or rectal swabs.
He explained that he does not view self-sampling negatively. In fact, even within clinics, patients are usually asked to collect their own samples in private, so the concept itself is already well established in practice.
He argued that reliable STI tests are already available, offering high sensitivity and specificity. As examples, he mentioned the pilot project run by the city of Zurich, which provides free STI testing for residents under 25, and the initiative by Aids-Hilfe Schweiz, which distributed self-tests during the COVID-19 lockdown. However, the latter had to be discontinued after Swissmedic, the national regulatory authority, intervened.
From his perspective, people who show symptoms already tend to seek testing directly at medical practices. For that reason, he argued, the true value of our test would lie in screening asymptomatic individuals, where infections often remain hidden and transmission chains continue unnoticed.
When we turned to treatment, he clarified that not every positive result automatically requires therapy—for example, Trichomonas infections do not always need treatment. In contrast, HIV and Syphilis must always be treated without exception. For Chlamydia and Gonorrhea, he pointed out, the situation is less clear, as there is still ongoing debate about whether asymptomatic infections should be treated systematically.
Based on the insights provided by Prof. Dr. med. Braun, we refined our project design to better reflect clinical realities. His input helped shape several key adjustments, ensuring that our diagnostic test is practical, reliable, and aligned with how STIs are detected and managed in everyday medical practice.
However, we decided against testing for HIV, even though it is one of the most important pathogens in STI screening. In Switzerland and many other countries, commercially available self-tests for HIV already exist, are widely distributed and are considered reliable by health authorities. Instead of duplicating these, we focused on pathogens for which there are no easily accessible self-testing solutions - closing the gap to self testing for STIs.
Overall, this expert input pushed us to refine our approach: to prioritize pathogens of highest clinical relevance, avoid tests with limited actionable outcomes, and adjust our sampling strategy to better reflect the epidemiology of STIs. These changes make our test design more robust, realistic, and impactful.