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Case definition & ascertainment

Case definition

To be considered a case for this surveillance system, the case patient must be a resident of one of the defined surveillance areas (as determined by the postal code of residence) and one of the following case definitions must be met:

  • Group A streptococcus is identified in a sample from a normally sterile site* or from a wound culture that accompanies a diagnosis of necrotizing fasciitis or streptococcal toxic shock syndrome (STSS)
  • Group B streptococcus is identified in a sample from a normally sterile site*
  • Neisseria meningitidis is identified in a sample from a normally sterile site*
  • Streptococcus pneumoniae is identifed in a sample from a normally sterile site* or the respiratory tract
  • Influenza is identified from a nasopharygeal or respiratory specimen

*such as blood, cerebrospinal fluid (CSF), pleural fluid, peritoneal fluid, pericardial fluid, surgical aspirate, bone, joint fluid, or internal body site (e.g., lymph node, brain)

Case ascertainment

TIBDN case finding is laboratory-based. Microbiology laboratories in acute care hospitals and reference laboratories providing services for residents of the surveillance areas report eligible cases to the study office as they are identified. The TIBDN study office provides a unique identifier for the case and requests shipment of the isolate to the study lab. The office is in regular contact with participating laboratories to ensure that cases are being actively reported. In addition, an annual audit is performed in all laboratories to identify any cases that may have been missed through the regular reporting process.

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