Investing on quality, quantity, neurophils and mucin test for 30 joint fluid samples collected from 30 patients with various arthral conditions, comparing to control subjects in Arthral-Skeletal Department of Bach Mai Hospital from Mar. 2002 to Jun. 2002. Results: There were changes in macroscopy: the volume of joint fluid was more than 5ml, light or dark yellow, lack of transparency, completely reduced viscosity. Test mucin was positive range from (++) to (+++), counts of white blood cell and neurophil increased. It was suggested that mucin and joint fluid cell studies can add for diagnosis of some arthral conditions.