432. Qualitative Differentiation of Genital Ulcer Disease Etiology via Nucleic Acid Amplification Testing (NAAT)

BACKGROUND: Genital ulcers (GUs) remain a common reason that both men and women seek treatment at US sexual health clinics. Presumptive diagnosis based solely on the macroscopic lesion characteristics is insensitive for differentiating between the common etiologies of GUs, which include HSV1/2, VZV, and syphilis. Given the ongoing and rapidly-expanding Syphilis epidemic, more accurate and timely identification of GU etiology would facilitate accurate therapeutic decision making, promote antibiotic stewardship, and have positive impacts on public health. The current study describes diagnostic workflows that allow for sequential/reflex or parallel GU testing, relying on a combination of IVD and published NAAT-based solutions, performed on the cobas® 4800 and/or cobas® 6800 Systems, to detect HSV1/2, VZV, and T. pallidum from a single specimen. METHODS: Commercially available control material for HSV1, HSV2, VZV, and T. pallidum were spiked into MSwab™ and cobasâ PCR medium at varying concentrations. The spiked medium was either aliquoted directly to cobas® PCR Media Secondary Tubes (for testing on the cobasâ 6800 System) or MSwabs were dipped directly into the spiked specimen vials and transferred to their respective collection tubes (cobasâ 4800 System). GU testing on the cobas® 4800 System was sequential: performing the cobas® HSV1 and 2 Test first, followed by VZV and T. pallidum detection using residual DNA eluates and the User Defined Workflow (UDF) software. Testing on the cobas® 6800 System allowed for parallel processing and simultaneous detection of the 4 targets utilizing the cobas omni Utility Channel, which supports a complete, automated Lab Developed Test workflow. RESULTS: Qualitative detection of HSV1, HSV2, VZV and T. pallidum was demonstrated on both systems. CONCLUSION: Novel solutions that aim to reduce empiric therapy, or shorten the interval to treatment success, are critical for both diagnostic and antibiotic stewardship. Through parallel or sequential testing algorithms, panel testing schematics on either the cobas® 4800 and 6800 Systems allow for more accurate discrimination between GU etiologies that may help address the re-emergence of Syphilis in the USA. DISCLOSURES: All authors: No reported disclosures.