Nailfold video capillaroscopy in patients with suspected systemic sclerosis: a comparison of one-finger method versus eight-finger method.

Objective: We evaluated whether nailfold video capillaroscopy (NVC) of one finger is an adequate alternative to detect scleroderma pattern in patients suspected of systemic sclerosis (SSc) compared with the usual eight-finger method. Methods: In this study, NVC images of 87 patients suspected of SSc were analysed for capillary density, capillary dimension, capillary morphology, the presence of microhaemorrhages and pattern. Each individual finger was compared with the eight-finger method using Cohen's kappa agreement. Finally, a two-finger and four-finger combination was analysed using the fingers with highest agreement. Results: After inclusion of 76 patients, NVC of a single finger showed weak to moderate agreement with the eight-finger method in detecting a scleroderma pattern with a Cohen's kappa value ranging from K=0.23 (right digit V) to K=0.47 (right digit IV). NVC of digit IV of both hands provided moderate agreement (K=0.63), whereas a four-finger combination of digit III and IV of both hands provided strong agreement (K=0.82). For detection of giant capillaries and capillary density <7 /mm, the four-finger method provided K=0.82 and K=0.52, respectively. The digit IV of the right hand provided the highest agreement among all the individual fingers for NVC pattern, giant capillaries and capillary density. Conclusion: NVC of a single finger does not represent a reliable alternative for the eight-finger method because of a weak to moderate level of agreement. A four-finger method using digit III and IV of both hands shows strong agreement and could be considered in clinical practice to optimise time efficiency.