Development and evaluation of dried urine strip for genital chlamydia and gonorrhea testing

Here, we developed and evaluated a filter-paper urine collection method for chlamydia and gonorrhea testing. Dried urine strips (DUS) were developed to fit into the sample collection tube used for high throughput Hologic Aptima Combo 2 assay, minimizing processing post-sample collection. Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) bacterial stock dilutions were used to assess DUS performance and long-term stability at different temperature conditions. DUS diagnostic performance was evaluated against urine samples with Aptima Combo 2 Assay and an in-house RT-PCR method for CT and NG detection utilizing residual diagnostic urine specimens (n = 60 CT and NG negative, n = 50 CT-positive and n = 55 NG-positive, including 5 CT/NG dual-positive). Replacing the overnight strip drying step with use of additional desiccants was evaluated in order to reduce barriers to self-sample collection. We observed a high degree of diagnostic accuracy (>91% sensitivity and >98% specificity), compared to traditional urine samples across all evaluated DUS preparation and storage methods. DUS samples demonstrated high stability for prolonged periods at tested temperature storage conditions with some loss in sensitivity at lower bacterial loads. While drying of the sample was crucial to preserve sample integrity and improve recovery post-elution, placing the DUS directly into the sample storage bag with additional desiccants did not negatively impact diagnostic performance. DUS specimens were shown suitable for downstream CT genotyping and NG sequence typing. The developed DUS represents an accurate and stable sample collection method for CT and NG diagnostic testing and downstream pathogen characterization. Importance: Innovative sampling methods that are convenient, accurate, and user-friendly are crucial to increase sexually transmitted infection (STI) testing uptake. This study establishes a novel dried urine strip sample collection method for chlamydia and gonorrhea testing and downstream molecular characterization. Results show no inferiority of dried urine strips compared to urine, with regard to diagnostic performance, when analyzed using molecular in-house and commercial assays for chlamydia and gonorrhea detection. A dried urine strip sample collection method for chlamydia and gonorrhea testing offers significant advantages in resource-limited or stigmatized settings; it enables self-collection, mail-in return, and long-term storage at ambient temperatures, making it ideal for reaching underserved populations. The broader public health impact is the expansion of STI screening access and reduction in STI transmission by offering a discreet, scalable alternative to traditional specimen collection.