THE LEVINSON RATIO AND THE TRYPTOPHAN TEST: COMPARATIVE VALUE IN THE DIAGNOSIS OF TUBERCULOUS MENINGITIS

THE LEVINSON RATIO  In 1917 Tashiro and Levinson¹ described a test of the spinal fluid which was considered diagnostic for tuberculous meningitis. It was based on differential precipitation of the proteins of the spinal fluid by mercury bichloride and by sulfosalicylic acid, depending on the pH of the fluid. The result of the test, known as the Levinson ratio, is considered positive if the amount of precipitate obtained by the action of mercury bichloride on the spinal fluid is at least twice as great as that obtained by the action of sulfosalicylic acid.Several studies² made since that time indicate that the Levinson ratio is positive for 78 to 100 per cent of specimens of spinal fluid obtained from patients ill with tuberculous meningitis. Less agreement is to be found in the results from control tests of spinal fluids taken from normal persons and from patients ill