The purpose of this retrospective clinical trial is to establish the clinical performance of the iStatis Syphilis AbTest. The data will be used to demonstrate the product is safe and effective for its intended use. The data obtained will be used in the application for CE certification under In Vitro Diagnostic Medical Device Regulation (IVDR) and World Health Organization (WHO) prequalification.

The objectives of this study are to establish the diagnostic sensitivity and diagnostic specificity of the iStatis Syphilis Ab Test. Left-over samples stored at -80ᵒC from the previous trials conducted by Epicentre will be used for this study. The samples are tested in a routine testing environment. Serum samples were tested for evidence of syphilis infection using a non-treponemal Rapid Plasma Reagin (RPR) assay. All reactive samples were further tested quantitatively.

Inclusion Criteria:

1. Anti-Tp negative samples:

   -Stored at ≤ -80°C.

2. Anti-Tp negative samples - pregnant women:

   • Samples from pregnant women, 1st and multipara
   • Samples found negative or false reactive for anti-Tp assay with the reference method.
   • Stored at ≤ -80°C.

3. Anti-Tp positive samples:

   • Samples screened with Abbott Architect Syphilis Tp and confirmed positive with BD Macro-Vue Particle Agglutination (RPR) and Serodia Particle Agglutination (TPPA).
   • Stored at ≤ -80°C.

4. Anti-Tp positive samples - pregnant women:

   • Samples from pregnant women
   • Samples screened with Abbott Architect Syphilis Tp and confirmed positive with BD Macro-Vue Particle Agglutination (RPR) and Serodia Particle Agglutination (TPPA).
   • Stored at ≤ -80°C.

Exclusion Criteria:

• N/A

Retrospective cross-sectional study on left-over samples stored at -80°C from previous trials conducted by Epicentre Heath Research.