RESUMO
BACKGROUND: Treponema pallidum specific serology generally remains reactive for life. Therefore, the diagnosis of syphilis reinfection relies on clinical assessment and nontreponemal (reagin) serologic testing. The prozone phenomenon can lead to a falsely nonreactive rapid plasma reagin (RPR) assay result. METHODS: We report a case of secondary syphilis in a HIV infected patient with a previous history of syphilis infection, where a falsely nonreactive RPR assay was associated with a delayed diagnosis of reinfection and infectious syphilis. The prozone phenomenon was detected in several of the patient's serum samples collected around this time. We subsequently undertook a prospective evaluation for the prozone phenomenon in 3222 consecutive sera, which were assayed using the RPR assay for clinical purposes over a 10-month period. RESULTS: The overall rate of the prozone phenomenon was 2 out of 3222 samples (0.06%; 95% confidence interval (CI): 0.02-0.22%) and the rate per reactive sample was 2 out of 397 (0.5%; 95% CI: 0.14-1.81%). CONCLUSION: Clinicians should request RPR testing at dilutions of sera when syphilis is suspected clinically and the RPR assay is nonreactive.
Assuntos
Sorodiagnóstico da Sífilis/estatística & dados numéricos , Sífilis/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/transmissão , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/diagnóstico , Transtornos Relacionados ao Uso de Anfetaminas/epidemiologia , Antibacterianos/uso terapêutico , Comorbidade , Estudos Transversais , Reações Falso-Positivas , Humanos , Masculino , New South Wales , Penicilina G Procaína/uso terapêutico , Estudos Prospectivos , Recidiva , Parceiros Sexuais , Sífilis/epidemiologia , Sífilis/transmissão , Carga ViralRESUMO
We report three cases with misleading cytomegalovirus (CMV) or Epstein-Barr virus (EBV) immunoglobulin M (IgM) results during primary human immunodeficiency virus (HIV) infection. We determined the rate of positive anti-CMV IgM assays or anti-EBV capsid antigen IgM assays in sera from a group of well-characterized subjects with primary HIV infection as 2.9% (1/35; 95%CI: 0.15-16.6%) for each infection. The rate of positive anti-EBV capsid antigen IgM assays in subjects with positive hepatitis A virus IgM assays was 30% (6/20; 95%CI: 14.6-51.9%). Clinicians need to consider the limitations of IgM assays for diagnosis of herpesvirus infections, and consider testing for other infections with overlapping clinical manifestations.
