Method for differential diagnosis of meningitis with a limulus lysate test

A method for rapid bedside diagnostic differentiation between aseptic meningitis and Gram-negative bacterial meningitis comprising:

• 1. providing three transparent sterile, pyrogen- and endotoxin-free closable vessels, the three vessels being individually identifiable as a positive control vessel, a negative control vessel and a test vessel, wherein each vessel contains an equal amount of lyophilized Limulus lysate and the positive control vessel also contains an amount of lyophilized Gram-negative bacterial endotoxin, said lyophilized lysate and endotoxin being inactive and essentially unreacted but being capable of reactivation upon the addition of water and/or cerebo-spinal fluid thereto;
• 2. placing cerebro-spinal fluid in the test vessel and pyrogen- and endotoxin-free water into each of the positive control vessel and the negative control vessel;
• 3. placing the three vessels in an environment at a temperature of between 15.degree. C and 45.degree. C;
• 4. incubating the three vessels in an undistrubed manner in the environment for at least 15 minutes so as to reactivate the Limulus lysate for reaction with the endotoxin in the positive control vessel and with any endotoxin in the test vessel;
• and
• 5. inverting each vessel, whereby the degree of the resulting clotting and/or turbidity in the test vessel may be visually compared with that in the positive control vessel and negative control vessel and a test result can be concluded from the comparison, the amount of lyophilized Limulus lysate contained in the re-activated condition being such that will produce a firm clot when treated with from 0.02 to 0.08 ng of standard Klebsiella endotoxin per ml of re-activated Limulus lysate.