title: Serological diagnosis of paracoccidioidomycosis: high rate of inter-laboratorial variability among medical mycology reference centers.
abstract: BACKGROUND
  Serological tests have long been established as rapid, simple and inexpensive tools for the diagnosis and follow-up of PCM. However, different protocols and antigen preparations are used and the few attempts to standardize the routine serological methods have not succeeded.
  
  
  RESULTS
  We compared the performance of six Brazilian reference centers for serological diagnosis of PCM. Each center provided 30 sera of PCM patients, with positive high, intermediate and low titers, which were defined as the "reference" titers. Each center then applied its own antigen preparation and serological routine test, either semiquantitative double immunodifusion or counterimmmunoelectrophoresis, in the 150 sera from the other five centers blindly as regard to the "reference" titers. Titers were transformed into scores: 0 (negative), 1 (healing titers), 2 (active disease, low titers) and 3 (active disease, high titers) according to each center's criteria. Major discordances were considered between scores indicating active disease and scores indicating negative or healing titers; such discordance when associated with proper clinical and other laboratorial data, may correspond to different approaches to the patient's treatment. Surprisingly, all centers exhibited a high rate of "major" discordances with a mean of 31 (20%) discordant scores. Alternatively, when the scores given by one center to their own sera were compared with the scores given to their sera by the remaining five other centers, a high rate of major discordances was also found, with a mean number of 14.8 sera in 30 presenting a discordance with at least one other center. The data also suggest that centers that used CIE and pool of isolates for antigen preparation performed better.
  
  
  CONCLUSIONS
  There are inconsistencies among the laboratories that are strong enough to result in conflicting information regarding the patients' treatment. Renewed efforts should be promoted to improve standardization of the serological diagnosis of PCM.
authors.affiliation: Medical Mycology Laboratory (IMTSP and LIM-53), Clinics Hospital of the Medical School and Tropical Medicine Institute, University of São Paulo (USP), São Paulo, São Paulo State, Brazil.
authors.forename: Monica Scarpelli Martinelli
authors.initials: MS
authors.lastname: Vidal
authors.affiliation: Medical Mycology Laboratory (IMTSP and LIM-53), Clinics Hospital of the Medical School and Tropical Medicine Institute, University of São Paulo (USP), São Paulo, São Paulo State, Brazil.
authors.forename: Gilda Maria Barbaro
authors.initials: GM
authors.lastname: Del Negro
authors.affiliation: Mycoses Immunodiagnosis Laboratory, Adolfo Lutz Institute, São Paulo (IAL-SP), São Paulo, São Paulo State, Brazil.
authors.forename: Adriana Pardini
authors.initials: AP
authors.lastname: Vicentini
authors.affiliation: Medical Mycology Laboratory, Laboratory of Teaching and Research in Clinical Analysis from Maringá(LEPAC), Maringá, Parana State, Brazil.
authors.forename: Teresinha Inez Estivalet
authors.initials: TI
authors.lastname: Svidzinski
authors.affiliation: Clinical Mycology Laboratory, Pharmaceutical Sciences School, São Paulo State University (UNESP), Araraquara, São Paulo State, Brazil.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Mendes-Giannini
authors.affiliation: Clinical Mycology Laboratory, Pharmaceutical Sciences School, São Paulo State University (UNESP), Araraquara, São Paulo State, Brazil.
authors.forename: Ana Marisa Fusco
authors.initials: AM
authors.lastname: Almeida
authors.affiliation: Serology Laboratory, Clinics Hospital, Ribeirão Preto School of Medicine (FMRPUSP), São Paulo State, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Martinez
authors.affiliation: Myco-serology Laboratory, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo (UNIFESP), São Paulo, São Paulo State, Brazil.
authors.forename: Zoilo Pires
authors.initials: ZP
authors.lastname: de Camargo
authors.affiliation: Medical Mycology Laboratory (IMTSP and LIM-53), Clinics Hospital of the Medical School and Tropical Medicine Institute, University of São Paulo (USP), São Paulo, São Paulo State, Brazil; Biomedical Sciences Institutes, Department of Microbiology, USP, São Paulo, São Paulo State, Brazil.
authors.forename: Carlos Pelleschi
authors.initials: CP
authors.lastname: Taborda
authors.affiliation: Medical Mycology Laboratory (IMTSP and LIM-53), Clinics Hospital of the Medical School and Tropical Medicine Institute, University of São Paulo (USP), São Paulo, São Paulo State, Brazil.
authors.forename: Gil
authors.initials: G
authors.lastname: Benard
mesh_terms: D000368:Aged; D001938:Brazil; D005260:Female; D006801:Humans; D007753:Laboratories / Q000145:classification*; D010229:Paracoccidioidomycosis / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D015203:Reproducibility of Results; D012698:Serologic Tests / Q000379:methods*