A syphilis point-of-care (POC) test which has excellent qualitative performance to screen and confirm syphilis will be assessed for its utility in quantitatively assessing treatment response and reinfection using an innovative microreader. Modeling how the different (treponemal and non-treponemal) antibody subtype concentrations correlate with the microreader results and how they vary in people living with and without HIV is crucial to optimize use of this simple, 15-minute assay. Use of this test at POC could obviate the need for laboratory- based testing, allow rapid treatment start and treatment monitoring to decrease onward transmission.