Trichomonas vaginalis and Mycoplasma genitalium Quality Controls: Ensuring rapid, low cost and sensitive STI tests are coming to a clinic near you

Quality controls have long been an essential part of good quality assurance programs in centralized diagnostic laboratories. However, as things change…either the types of tests being performed or the people who are performing them, quality controls become even more critical. Molecular diagnostic testing for Sexually Transmitted Infections (STIs) is changing rapidly. This article explains how testing is changing and how patient-like quality controls can help ease the transitions.

The Changing Landscape of STI Testing 

Trichomonas vaginalis (TV) and Mycoplasma genitalium (MG) are STIs that are very common, both within the US and globally with very significant clinical impact. TV is a protozoan pathogen that is curable, but since many infected individuals don’t experience symptoms, it can be left untreated. For women, untreated TV infection may result in increased risk of preterm birth and low birth weight in pregnancy as well as infertility. MG is a bacterial infection of the urogenital tract and antibiotic resistance is a growing concern.¹ It is also often asymptomatic but is a leading cause of persistent or recurrent non‑gonococcal urethritis in men, and in women its associated with cervicitis, Pelvic Inflammatory Disease (PID), preterm delivery, spontaneous abortion, and infertility.²

There is increasing demand for rapid and highly sensitive STI diagnostics. The adoption of rapid STI testing in the U.S. is driven by multiple factors, including the rising prevalence of STIs, increasing awareness of asymptomatic infections, and the need for timely diagnosis to prevent complications and transmission.³ Regional differences in STI prevalence can drive testing demand, but high prevalence regions include urban centers and underserved rural communities, where access to specialized laboratories may be more limited.

Therefore, test developers are integrating nucleic acid amplification tests (NAATs) into rapid testing platforms so that they can be deployed in community based healthcare settings. IVDs are focused on developing portable, lower cost, and easy to use testing systems that align better with decentralized testing. “Healthcare providers are increasingly prioritizing point-of-care testing to facilitate immediate treatment decisions, especially in high-risk populations such as sexually active young adults and underserved communities.” However, as test performance shifts from centralized laboratories run on fully automated systems by laboratory professionals to more community based settings, there could be concerns over test sensitivity and test operator training and proficiency.

Multiplex Testing Brings New Performance Challenges

An additional trend is toward multiplex tests, which are able to detect multiple STI’s simultaneously. However, in molecular tests, sensitivity often decreases in multiplex assays. This is because in NAATs, all targets share the same reaction mix (polymerase, dNTPs, Magnesium ions etc), but high abundance targets will consume these reagents faster and may cause low abundance targets to fail to amplify. This is particularly problematic when the pathogen loads vary significantly: for example, during co-infection Chlamydia trachomatis may be 100 – 100,000 times higher concentration than the MG. Additionally, when multiplexing, there may be compromises in primer/probe designs so that they all work under one thermal profile, and there is increased chance of primer-dimer formation and non-specific primer binding. As multiplexed tests are developed, validated and implemented, there is critical need to monitor the sensitivity and performance of each analyte in the test with quality control materials that closely mimic patient samples

Maintaining Confidence with Quality Controls 

Within the US, several rapid or point of care diagnostics already exist for TV detection (Table 1), and undoubtedly, more are in development. Rapid and POC tests for MG have been slower to be developed and currently only high complexity, high throughput assays (Aptima^® Mycoplasma genitalium Assay (Hologic), cobas^® TV/MG Test (Roche), or Alinity m STI Assay (Abbott)) are available in the US. One reason that development of rapid MG testing is slower is that there is a significantly lower organism burden during infection, which demands higher sensitivity detection. Table 2 shows companies currently developing MG Molecular Tests or companies well positioned for Rapid/POC MG entry.

Table 1: Rapid or Point of Care Molecular Diagnostics currently available in the US for TV detection. OTC = Over the counter. Note: Large, central laboratory based tests such as Aptima^® TV test by Hologic are not shown here.

Table 2: Potential Future Rapid diagnostics for MG. Note that incumbants like Hologic and Roche that currently offer high complexity, centralized laboratory test systems for MG are not listed.¹

Multiplex molecular diagnostics and community‑based STI testing will work synergistically to address persistent STI disparities. These more rapid tests will have a positive impact on underserved populations through improved access and timeliness as long as diagnostic accuracy is maintained. Quality controls such as ACCURUN^® TV/MG Positive Molecular Control help both test developers and test operators ensure that the tests performance and quality meet the needs of patients.

Check out previous related articles:

Global STI Surveillance is Built on Diagnostic Lab Speed, Accuracy, and Quality

5 Best Practices for Best-in-class Clinical Lab Quality Control

The Importance of Using Third-Party, Independent Quality Controls

References

1. Latest Advances in Laboratory Detection of Mycoplasma genitalium

2. Mycoplasma genitalium

3. Trichomonas Rapid Testing Market Size, Share, and Industry Trends Forecast 2026-2036