###Human: TPA is high but VDRL is negative. Please advice. ###Assistant: Hello. 1. As you have mentioned the TPA (Treponema pallidum antibody assay) is positive. 2. VDRL is nonreactive.3. Next step to confirm if you have latent syphilis, you need to get one of the following two tests first. A.TPHA (Treponema pallidum Haemagglutination assay). Or B. TPPA ( Trepenoma pallium particle agglutination assay). A. TPPA/TPHA B. HIV C. HBsAg D. Anti HCV Please revert back with the investigations I have asked for so that I can decide on the specific treatment plan for you.