Background It is estimated that everyday over 1 million individuals contract a curable sexually transmitted infection (STI) worldwide. For an appropriate STI treatment, it is necessary to have an accurate diagnosis. The Alinity m STI assay is a multiplex RT-PCR assay that identifies four STI pathogens: Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV), and Mycoplasma genitalium (MG) in a single (115 min) reaction. The aim of this study was to evaluate the assay clinical performance.

Methods Clinical performance of Alinity m STI assay was assessed using 201 residual clinical samples [119 urine and 82 in gynecological specimens] and compared with Abbott RealTime CT/NG assay and XGEN MULTI UP test (Mobius Life Science) for TV/MG. Precision and reproducibility were evaluated by testing panel members in contrived swab. Five panel members (PM) were tested in 12 replicates in two days: PM1=CT, PM2=NG, PM3=TV, PM4=MG and PM5=CT/NG/TV/MG at 2X claimed LoD.

Results For CT, the positive (PPA) agreement and negative (NPA) agreements were 95% and 100% respectively. For NG, the PPA was 94% for urine and 100% for gynecological specimens, and NPA was 99% and 100%, respectively. For MG, PPA and NPA were 100%. For TV, NPA was 100% (no positive result obtained). Co-infection with MG was observed in 5% of CT or NG positive samples. The overall agreement for both sample types and the four organisms was 98.5% (516/524). All panel members were detected and accurately identified, individually (PM1–4) or in the presence of the other three pathogens (PM5).

Conclusion The Alinity m STI assay showed excellent agreement (97–100%) between methods and streamlines laboratory workflow with simultaneous detection of 4 pathogens in a single reaction from the same sample. This assay allows rapid infection identification supporting clinicians to properly treat patients, especially when a co-infection is present.