Meningococcal disease manifests most commonly as meningitis and/or meningococcemia that may progress rapidly to purpura fulminans, shock, and death. However, other manifestations might be observed.
Isolation of Neisseria meningitidis from a normally sterile site (e.g., blood or cerebrospinal fluid [CSF] or, less commonly, joint, pleural, or pericardial fluid)
A case with a positive antigen test in CSF or clinical purpura fulminans in the absence of a positive blood culture
A clinically compatible case that is laboratory confirmed
Positive antigen test results from urine or serum samples are unreliable for diagnosing meningococcal disease.