This Study Evaluates the ALPCO Syphilis-T and Syphilis-NT CLIA Kits for Detecting Syphilis Antibodies in Serum and Plasma. Samples From At-risk, HIV-positive, Pregnant, and Healthy Individuals Will Assess Assay Performance Versus Established Comparator Tests.

Inclusion Criteria: * Male, Female, or Other(s) * Patients undergoing routine syphilis testing (asymptomatic at risk, suspected with symptoms, prior history of syphilis, high risk for syphilis) or previously diagnosed with syphilis through a test performed in an accredited laboratory. * Participants must be willing to provide the required blood samples for the clinical study, in addition to any samples requested by their physician. * Pregnant individuals and children (under 22): 1 clinical study tube of blood. * All other participants (excluding pregnant individuals and children): 2 clinical study tubes of blood. * Participants must be able and willing to sign the informed consent form (ICF). * Participants aged 13 to 17 will be asked to sign an assent form. Written parental or guardian consent will also be required prior to enrollment. The assent form will use age-appropriate language and be reviewed with the participant before any procedures. Exclusion Criteria: * Patients currently being treated with antibiotics or completed a course of antibiotics within the past 30 days * Patients with pre-existing conditions that would make blood collection difficult or harmful * If the samples are not collected in strict accordance with the established sampling protocol, as determined by the study team. * Any medical, psychological, or social condition that, in the judgment of the investigator, could interfere with the participant's ability to comply with study requirements, or pose a risk to their safety, or compromise the integrity of the study.