Lactate dehydrogenase in synovial fluid diagnostic evaluation of total activity and isoenzyme patterns.

The work of Ropes and Bauer (1953) has focused attention on the analysis of synovial fluid in the differential diagnosis of joint effusion. White blood cell total and differential counts, glucose assay, and mucin precipitation tests have thus all been applied to the distinction of non-inflammatory, mild inflammatory, severe inflammatory, and infectious effusions. These analyses do not, however, indicate the true origin of the effusion, and we have carried out this investigation to find out whether differential assay of lactate dehydrogenase (LDH) isoenzymes could yield more specific information.