Meningococcal disease presents most commonly as meningitis and/or meningococcemia that may progress rapidly to purpura fulminans, shock, and death. However, other manifestations may be observed.
Isolation of Neisseria meningitidis from a normally sterile site
A positive antigen test in cerebrospinal fluid or clinical purpura fulminans in the absence of a positive blood culture
A clinically compatible case that is culture confirmed
Antigen test results in urine or serum are unreliable for diagnosing meningococcal disease.