The intra-observer, diurnal and week-to-week variations in grip and pinch strength was studied in patients with rheumatoid arthritis.

The changes in grip and pinch strength in duration of the illness and medications was observed and the correlation between grip and pinch strength was studied, as following:

A high correlation was seen between grip and pinch strength. In the intra-observer errors studies, the highest grip and pinch strength scores occured in the 3rd test, but no statistically significant change was recorded among 1st, 2nd, 3rd. In week-to-week variations, a statistically significant change was recorded.

In the diurnal variations, some data were statistically significant, but others were not statistically significant. In clinical trials, measurement of grip and pinch strength should not only be performed by one observer for each patient but measurements should be made at the same time of day because of its diurnal variation.