A negative toluidine red non-heating serologic test is mostly indicative of a good case. Toluidine red non-heating serologic test is a syphilis screening method, which is a non-syphilis spirochete antigen serologic test, and can be used to screen the population for syphilis. A negative test indicates a negative syphilis screen, which can rule out syphilis infection to some extent. However, it is also possible that the infection with the syphilis spirochete was short-lived and in the window period, and not enough antibodies were produced in the blood to present a false negative. However, if the patient has a past history of impure sexual intercourse, or has a severe chancre or symptoms of second- or third-degree stage syphilis with skin, mucosal, and oral abnormalities, a serologic test for syphilis spirochete antigen is necessary to further clarify the diagnosis. Patients who still suspect that they may be infected with syphilis after a negative toluidine red non-heating serologic test are advised to seek prompt medical attention for the next step of testing and treatment under the guidance of a doctor.