False-positive Rapid Plasma Reagin Tests in Human Immunodeficiency Virus Infection and Relationship to Anti-Cardiolipin Antibody and Serum Immunoglobulin Levels

J Infect Dis. 1994 Jun;169(6):1356-9. doi: 10.1093/infdis/169.6.1356.


The incidence of biologic false-positive rapid plasma reagin (RPR) tests may be increased in human immunodeficiency virus (HIV) infection; however, injecting drug use has not been excluded as the cause. Review of 3371 periodic syphilis serology results from 1077 HIV-seropositive patients in the United States Air Force HIV Natural History Study between January 1986 and June 1992 revealed a cumulative biologic false-positive RPR rate of 1%. Most (6/9) were transient low-titer results associated with a recent acute infectious process. False-positive RPR tests did not appear to correlate with anticardiolipin antibody levels or serum IgG or IgA levels, which are increased in HIV infection. Although not statistically significant, there was a trend toward higher IgM levels in patients with biologic false-positive tests. Thus, the incidence of false-positive RPR in an HIV-infected population with a low risk of injecting drug use is similar to that in the general population, and the mechanism may correlate with elevated serum IgM levels.

MeSH terms

  • Analysis of Variance
  • Antibodies, Anticardiolipin / blood*
  • Antibodies, Viral / immunology
  • False Positive Reactions
  • Female
  • HIV Infections / blood
  • HIV Infections / diagnosis*
  • HIV Infections / immunology
  • Humans
  • Immunoglobulin M / blood
  • Male
  • Syphilis Serodiagnosis


  • Antibodies, Anticardiolipin
  • Antibodies, Viral
  • Immunoglobulin M