The sulphated glycosaminoglycan levels in synovial fluid aspirates in patients with acute and chronic joint disease. Proteoglycan levels were measured in a series of synovial fluid samples from patients with acute and chronic joint diseases using a modified chemical dye binding method. Levels found in 50 miscellaneous inflammatory arthritis fluids (mean = 173.2 +/- 90.9 micrograms/ml) were higher than found in either 50 with rheumatoid arthritis (96.3 +/- 31.3 micrograms/ml) or 50 with osteoarthritis (83.8 +/- 27.3 micrograms/ml). For comparison, proteoglycan levels were measured in 15 cadaver synovial fluids (98.9 +/- 44.2 micrograms/ml) and 12 synovial fluids from patients with sports injury (163.7 +/- 79.4 micrograms/ml). Patients were recruited into a trial where synovial fluid was aspirated as often as possible over a 6-month period during which the patients were followed using a number of well proven clinical parameters. No correlation was found between the degree of joint destruction as measured by X-ray damage and the concentration or total amount of proteoglycan in the synovial fluid. In addition, there was no correlation between the level or total amount of proteoglycan and any clinical parameter of disease activity. 