Modern methods for determining cerebrospina! fluid proteins

A simple and rapid micro method for the determination of albumin and total protein in cerebrospinal and other body fluids is presented. It is based on the UV spectro-photometric measurements of neutral and acid-alcohol-treated spinal fluid and is shown to be accurate and reproducible. Using spectrophotometry at 220 m and two other recently improved technics, 84 specimens of spinal fluid from infants were analyzed for total protein. The results obtained showed good agreement over the range 30-200 mg./100 ml. SUGGESTED IMPRovEMENTs in two technics widely used clinically for estimating spinal fluid protein stimulated the inception of a compara-tive study which is reported below. Meulemans (1) demonstrated the necessity of adding sufficient so-dium sulfate to salicylsulfonic acid (SSA) in order to eliminate an error in protein estimation caused by albumin and globulin giving unequal amounts of turbidity with aqueous SSA (2). The turbidity method of Meulemans is presently studied because of its simplicity. The Folin-Ciocalteu copper technic as originally adapted by Dougha-day et al. (3) for spinal fluid protein estimation has been shown to be unreliable unless a blank of deproteinized spinal fluid is analyzed at the same time (4, 5). The latter suggestion has now been followed. Rieder (6) studied the ultraviolet spectral curves of cerebrospinal fluid and concluded that direct spectrophotometry in the region of 260-280 m was unreliable for the determination of protein. In the present work, ultraviolet spectrophotometry according to Tombs et al. (7) has been successfully applied and shown to be capable of excellen