An Investigation of Non-specific Reactions in Measurement of Plasma (1-3)-^|^beta;-D-glucan

We investigated the detection of non-specific reaction in measurement of plasma (1-->3)-beta-D-glucan (beta-glucan) by alkaline treatment, chromogenic automated kinetic assay (alkaline-kinetic assay) and dilution and heating method, chromogenic endpoint assay (dilution heating endpoint assay). In this study, we reexamined the values of beta-glucan by both methods with and without 4-amidinophenyl benzoate hydrochloride (APB) as protease inhibitor that blocks Limulus reaction in the 142 serum samples from 142 patients who had been treated and measured beta-glucan in Kawasaki medical school hospital between January 1999 and May 1999. Non-specific reactions were judged by the calculated value under APB additive condition. The non-specific reactions were found in 135 of total 142 samples (95.1%) in the alkaline-kinetic assay while no non-specific reactions were recognized in dilution heating endpoint assay. The alkaline-kinetic assay has been used widely and been evaluated it's usefulness because of good sensitivity. However, we found very high frequency of nonspecific reaction in this method. Further studies are needed to define the reasons of non-specific reaction. On the other hand, although non-specific reactions were not detected in dilution heating end-point assay, it's clinical utilities should be evaluated in future clinical studies.