Assessment of the benzethonium chloride method for routine determination of protein in cerebrospinal fluid and urine

Abstract

We have tested the characteristics of the method of Iwata and Nishikaze. The linearity, sensitivity, and precision are satisfactory and the reactivity of benzethonium chloride with various proteins (albumin, immunoglobulins) is the same. The method has been compared with Meuleman's technique, routinely used in our laboratories, by analysis of 82 samples of cerebrospinal fluid (CSF) and 119 samples of urine. Our results for cerebrospinal fluid agree well with those if Iwata and Nishikaze (r = 0.976; y = 0.992x - 0.013), but we find their method unsuitable for urinary protein determination, probably because of interfering compounds in urine.