A new immunochemical purity test for clinical dextran. Methodology and studies on clinical dextran preparations

A simple immunochemical procedure, based on reversed single radial immunodiffusion (RSRI) was developed to detect commonly occurring traces of antigenic contaminants in clinical dextran. High-titred antisera against non-dextran components of Leuconostoc mesenteroides NRRL B512 were produced and served as analytical reagents. Dextran samples were incorporated into a gel layer. Presence of contaminants is revealed by precipitate formation following application of antiserum to a well cut into the gel. Antigenic contaminants can be detected in concentrations exceeding 10 ppm by the Leuconostoc-RSRI test. Screen results on 119 clinical dextran samples from manufactures in different countries disclosed presence of antigen traces in 82% of preparations. Introduction of the new test and improved purification measures at Pharmacia AB resulted in purer clinical dextran with negative RSRI test scores in 99% of batches produced. Only batches passing this test are released for clinical use. Although no direct correlation was found between contaminant levels and incidence of dextran reactions, antigenic contaminants may play a contributory role in elicitation of mild reactions.