RT Journal Article SR Electronic T1 Comparative study of C reactive protein and serum amyloid A protein in experimental inflammation. JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP 677 OP 679 DO 10.1136/ard.50.10.677 VO 50 IS 10 A1 Chambers, R E A1 Hutton, C W A1 Dieppe, P A A1 Whicher, J T YR 1991 UL http://ard.bmj.com/content/50/10/677.abstract AB The responses of C reactive protein, measured by radial immunodiffusion and radioimmunoassay, and serum amyloid A protein, measured by radial immunodiffusion, were compared in eight subjects with inflammation induced experimentally by intradermal injection of monosodium urate crystals. A significant increase in serum amyloid A was noted after a lag phase of eight hours, the increase in median concentration at 48 hours being about eightfold. A parallel but less marked increase was found in C reactive protein when measured by radioimmunoassay (fourfold increase in median concentration at 48 hours) after a small but significant decrease during the lag phase. The changes in C reactive protein remained within the reference range and were not detectable by radial immunodiffusion.