The diagnostic value of nailfold capillaroscopy was assessed through blind analysis of a continuous series of 307 examinations and a method for quick reading of nailfold capillaroscopy was elaborated with discriminant analysis. The best criteria for predicting the existence of a systemic disease were: major dystrophies (megacapillary, neocapillary and regressive capillary), minor dystrophies and capillary bed abnormalities, especially in patients presenting with vascular disorders of the upper extremities. Capillaroscopic stages and existence of systemic disease were significantly correlated. Discriminant analysis could globally predict the existence of a systemic disease with age and 4 criteria. In subjects with vascular disorders of the upper extremities it needed only age and 3 criterias (abnormal coloration, major dystrophy presence and percentile of minor dystrophies greater than 15%) but without higher diagnostic value (94.2% of patients with systemic disease and 65.6% of patients without systemic disease were correctly classified). Discriminant analysis allows quick reading of nailfold capilloroscopy in the first examination of patients with vascular disorders of the upper extremities.