A negative rapid plasma reactive element test indicates low reactive element antibodies and can be seen in the absence of syphilis, cured syphilis, and untreated advanced syphilis. When syphilis invades the body, two types of antibodies, specific and non-specific, can develop, and the non-specific antibodies are called reactin antibodies. The rapid plasma reactive element test uses cardiolipin as the antigen to test the level of non-specific syphilis antibodies in the blood, and a negative result means that the reactive element antibody level is low. Low levels of non-specific antibodies to syphilis can be seen in normal people who do not have syphilis, i.e., who do not have reactin antibodies in their bodies. When syphilis is actively treated, the level of non-specific syphilis antibodies in the body also decreases, and the level reaches the standard of a negative test. When syphilis is left untreated and develops into advanced syphilis, the level of non-specific antibodies also decreases in some patients, resulting in a negative test result. The rapid plasma reactive element test is highly sensitive but less specific. It is recommended to seek medical advice and standardize treatment under the guidance of a medical professional.