Diagnosis of deep-vein thrombosis of the legs.

The reported incidence of deep-vein thrombosis in hospital patients varies from less than 1 % (Barker et al., 1940 ; Felder, 1949) to over 28% (Sevitt and Gallagher, 1959). This wide variation reflects not only differences in the populations at risk but also differences in the criteria of diagnosis and in the vigilance with which they are sought. There is general agreement that the clinical diagnosis of deep-vein thrombosis may be difficult or impossible, and the occurrence of pulmonary embolism without previous recognition of its cause is common experience. The usually accepted signs of deep-vein thrombosis