A lady who recently has had surgery for varicose veins has developed a swelling below the knee. The surgeon wants to know whether the fluid drained from the swelling is synovial fluid or not. Does anybody have any ideas? I thought viscosity may help, but what's the expected range in normal fluid? Peter Hudson Principal Biochemist Wrexham Maelor Hospital Wales, UK [log in to unmask] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%