A simple stained protein assay (SPA) for rapid total protein determination applied to spinal fluids

A rapid, simple technique measures small amounts of total protein applied on an agarose gel slab. Alternating current through the gel may reduce diffusion of the protein, which is chemically fixed. The intensity of the Coomassie-Blue-stained spots is a function of the amount of protein determined by comparison with simultaneously run standards. Densitometric and visual estimates of protein in spinal fluids by the stained protein assay correlated with Lowry values highly significantly (n = 28; P less than 0.001, Spearman test of rank correlation). As little as 0.2 mug protein was measured; this figure should be compared with 10 mug for the Lowry method. The reproducibility of the method was +/- 5%.