Seven different assays of hyaluronan compared for clinical utility

To compare six assays of hyaluronan (hyaluronic acid; HYA) in serum, developed in different laboratories, we analyzed 10 samples from each of three groups: healthy persons, patients with primary biliary cirrhosis, and patients with rheumatoid arthritis. All the assays are based on the use of affinity proteins specific for HYA, prepared from cartilage or brain tissue, and are analogous to RIA or enzyme immunoassay techniques. The assay results were of the same magnitude. Although statistical analysis indicated that the methods in some cases deviated significantly from one another, this variation was less than the physiological variation in the healthy population. Therefore, the results of clinical investigations in which the various methods have been used are comparable. The analyses have high specificity and sensitivity for primary biliary cirrhosis but are somewhat less suitable for detecting rheumatoid arthritis. A seventh laboratory, which obtained antibodies to HYA, used these in an RIA to analyze a separate series of serum specimens. Results were in agreement with those obtained by one of the other assays.