title: Evaluation of Commercial Assays for Single-Point Diagnosis of Pertussis in the US.
abstract: BACKGROUND
  Pertussis serodiagnosis is increasingly being used in the United States despite the lack of a US Food and Drug Administration-approved, commercially available assay. To better understand the utility of these assays in diagnosing pertussis, serology assays were evaluated for analytical parameters and clinical accuracy.
  
  
  METHODS
  Forty-three antigen-antibody combinations were evaluated for single-point diagnosis of pertussis. Serum panels included sera from laboratory-confirmed cases, an international reference standard, and healthy donors. Phase I panel (n = 20) of sera was used to assess precision, linearity, and accuracy; Phase II panel (n = 226) followed with positive percent agreement (PPA) and negative percent agreement (NPA) estimates. Analytical analyses included coefficients of variation (CV) and concordance correlation coefficients (rc).
  
  
  RESULTS
  Intra-analyst variability was found to be relatively low among samples per assay, with only 6% (78 of 1240) having CV >20%, primarily with the highly concentrated immunoglobulin (Ig)G anti-pertussis toxin (PT) specimens and IgM assays. The rc measurements to assess linearity ranged between 0.282 and 0.994, 0.332 and 0.999, and -0.056 and 0.482 for IgA, IgG, and IgM, respectively. Analytical accuracy for calibrated IgG anti-PT assays was 86%-115%. The PPA and NPA varied greatly for all assays; PPA/NPA ranges for IgA, IgG, and IgM assays, with culture and/or polymerase chain reaction positivity as control, were 29-90/13-100, 26-96/27-100, and 0-73/42-100, respectively. In IgG assays, mixing filamentous hemagglutinin antigen with PT increased PPA but decreased NPA.
  
  
  CONCLUSIONS
  Seroassays varied substantially under both analytical and clinical parameters; however, those that were calibrated to a reference standard were highly accurate. Our findings support incorporation of calibrated pertussis seroassays to the pertussis case definition for improved diagnosis and surveillance.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Lucia C
authors.initials: LC
authors.lastname: Pawloski
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Plikaytis
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Monte D
authors.initials: MD
authors.lastname: Martin
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Stacey W
authors.initials: SW
authors.lastname: Martin
authors.affiliation: Focus Diagnostics, San Juan Capistrano, California.
authors.forename: Harry E
authors.initials: HE
authors.lastname: Prince
authors.affiliation: Focus Diagnostics, San Juan Capistrano, California.
authors.forename: Mary
authors.initials: M
authors.lastname: Lapé-Nixon
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: M Lucia
authors.initials: ML
authors.lastname: Tondella
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D000942:Antigens, Bacterial; D001886:Bordetella pertussis / Q000276:immunology* / Q000472:pathogenicity; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D037342:Pertussis Toxin / Q000276:immunology; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D014481:United States; D010566:Virulence Factors, Bordetella / Q000276:immunology; D014917:Whooping Cough / Q000175:diagnosis* / Q000276:immunology
chemical_list: D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic; D010566:Virulence Factors, Bordetella; C065273:filamentous hemagglutinin adhesin, Bordetella pertussis; D037342:Pertussis Toxin
keywords: Bordetella pertussis; ELISA; diagnostics; serology