Table 2.
Considerations regarding the validity of syphilis serological blood tests according to the European Centre for Disease Prevention and Control14
| False negative |
| Two- to four-week window between acquiring infection and production of sufficient antibody (IgM and/or IgG) to result in a positive test |
| A false-negative RPR/VDRL test may occur in secondary syphilis and early latent and early neurosyphilis |
| False-negative RPR/VDRL tests may occur in late-stage syphilis |
| Temporary negative serological tests have occasionally been reported in secondary syphilis |
| False positive |
| Autoimmune disease, HIV infection, pregnancy, and intravenous drug abuse |
| A false-positive antibody response to cardiolipin may be seen in pregnancy, postimmunization, recent myocardial infarction, in many febrile infective illnesses, in injecting drug users, autoimmune diseases, leprosy, chronic liver pathology and old age |
Abbreviations: HIV, human immunodeficiency virus; Ig, immunoglobulin; RPR, rapid plasma reagin test; VDRL, Venereal Disease Research Laboratory.