Capillary blood cell velocity in finger nailfold: characteristics and reproducibility of the local cold response.

The characteristics and reproducibility of nailfold capillary blood cell velocity (CBV) of the local cold response was evaluated in 30 cases by video-microscopy using a flying-spot technique. CBV, as well as flow stop duration during cooling, from a first and second test was significantly (P less than 0.05) reproducible, whether or not the test was repeated after 60 min or after an interval of 12 weeks. Because of interindividual variations in rest CBV, and a better reproducibility of the flow stop duration, this last parameter is more useful in clinical practice for follow-up evaluations of the local cold response test. The usefulness of the flying-spot generator for rapid and accurate measurement of CBV in finger nailfold capillaries is demonstrated in normal subjects and patients with primary Raynaud syndrome during a local cooling test.