Photometric Determination of Cerebrospinal Fluid Total Globulin and A/G Ratio with a Tryptophan Reaction

Abstract

Abstract A previously described colorimetric tryptophan procedure for determination of serum total globulin and A/G ratio was modified so as to increase its sensitivity and suitability for determination of the small amount of globulins present in cerebrospinal fluid. Twenty-seven normal CSF specimens analyzed with the tryptophan method yielded a mean total globulin value of 14.0 ± 3.03 mg./100 ml., and a mean A/G ratio of 1.45 ± 0.25. These data are in good agreement with those reported for normal CSF specimens with the paper-electrophoretic method. To demonstrate its clinical application in the diagnosis of neurologic disorders, the tryptophan method was used in the analysis of 51 CSF specimens from neurologic patients. Elevated total globulin values were obtained in 57 per cent. Six patients with normal total protein values showed decreased A/G ratios.