title: Trends in Pertussis Diagnostic Testing in the United States, 1990 to 2012.
abstract: BACKGROUND
  Reports of pertussis have been increasing in the US since the 1990s, and pertussis diagnostics have evolved during that time. Here, we describe temporal changes in pertussis diagnostic practices in the US during 1990 to 2012 and discuss potential implications.
  
  
  METHODS
  Pertussis cases reported through the National Notifiable Diseases Surveillance System during 1990 to 2012 were included in this analysis. Laboratory results were stratified by test type, case classification, age group and case-patient state of residence.
  
  
  RESULTS
  This analysis included 291,290 cases with 64% (n = 186,766) reporting at least 1 pertussis laboratory result. Culture and direct fluorescent antibody were the primary results reported during the early 1990s; however, polymerase chain reaction (PCR) surpassed all other test types during the late 1990s and 2000s. By 2012, more than 91% of cases with known results were tested using PCR, either alone or in combination with another test type. Before 2005, Massachusetts reported 71% of serology results, but an increasing number of states reported serologic results during 2005 to 2012. When stratified by age group, overall testing trends persist. As of 2012, culture confirmation is used infrequently across all ages, whereas the use of serology increases with age and is most prevalent among adults aged ≥ 20 years.
  
  
  CONCLUSIONS
  PCR has become the primary diagnostic method, and serologic assays now are used in a majority of states. Epidemiologic trends must be considered in the context of changing diagnostic tests, and modifications to surveillance case definitions should be considered to better reflect current testing practices.
authors.affiliation: From the *Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, †Immunization Services Division, National Center for Immunization and Respiratory Diseases, and ‡Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Faulkner
authors.forename: Tami H
authors.initials: TH
authors.lastname: Skoff
authors.forename: M Lucia
authors.initials: ML
authors.lastname: Tondella
authors.forename: Amanda
authors.initials: A
authors.lastname: Cohn
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Clark
authors.forename: Stacey W
authors.initials: SW
authors.lastname: Martin
mesh_terms: D001886:Bordetella pertussis; D003955:Diagnostic Tests, Routine / Q000379:methods; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D011159:Population Surveillance; D014481:United States / Q000453:epidemiology; D014917:Whooping Cough / Q000175:diagnosis* / Q000453:epidemiology* / Q000266:history