The Levinson test1 of the spinal fluid is used to help in making the diagnosis in cases in which tuberculous meningitis is suspected. Frequently one is unable to find tubercle bacilli in the spinal fluid. In the absence of autopsy and inoculation into guinea-pigs one relies primarily on the history, physical findings and clinical data. Additional tests are therefore welcome.
The Levinson test is based on the principle that protein in meningitic spinal fluid reacts electronegatively or electropositively in the presence of certain alkaloid or metallic precipitants. If one adds 3 per cent of sulphosalicylic acid solution (alkaloid precipitant) to epidemic cerebrospinal meningitic fluid (acid in reaction), the protein becomes electropositively charged (cataphoresis to cathode). If 1 per cent solution of mercuric chloride (metallic precipitant) is added to tuberculous meningitic spinal fluid (alkaline in reaction), the protein becomes negatively charged (cataphoresis to anode).
The H-ion concentration of the spinal fluid