1. A computer-implemented method performed on a dispatch center computer to assist a dispatcher when communicating with a caller via telephone regarding a medical emergency of a patient, comprising: providing on the dispatch center computer system an emergency dispatch protocol to assist the dispatcher, the protocol presenting a plurality of pre-scripted interrogatories for the dispatcher to ask the caller to gather information regarding the emergency and generate an emergency dispatch response by emergency responders; initiating a diagnostic tool on the dispatch center computer, the diagnostic tool configured to assist the dispatcher in guiding the caller to obtain information that can be used by the diagnostic tool to diagnose whether the patient has meningitis; the diagnostic tool presenting to the dispatcher a user interface comprising a diagnostic indicators pane and a criteria summary pane; the diagnostic tool providing one or more questions via the user interface, the questions being intended for the dispatcher to vocally relay to the caller over the telephone to guide the caller in identifying signs and symptoms that the patient has meningitis; the diagnostic tool receiving dispatcher-entered input indicative of caller-relayed information concerning the caller's observations of the patient, including signs and symptoms that indicate whether the patient has meningitis, wherein the caller's observations are vocally relayed over the telephone to the dispatcher; presenting, on the diagnostic indicators pane of the user interface of the diagnostic tool, a listing of one or more signs and symptoms that indicate whether the patient has meningitis that are received through the dispatcher-entered input; presenting, on the criteria summary pane of the user interface of the diagnostic tool, a plurality of tally fields to convey a basis for a likelihood that the patient meningitis, each tally field of the plurality of tally fields displaying a tally of signs and symptoms of a level of severity that is different from a level of severity corresponding to other of the plurality of tally fields; and the diagnostic tool determining a likelihood that the patient has meningitis based on the dispatcher-entered input indicative of the caller-relayed information and the tallies of signs and symptoms displayed by the plurality of tally fields.