Comments on reason for conflicting results of venography

Conflicting results of phlebography in the diagnosis of thrombosis in different investigations are discussed. The following factors may explain different results: phlebography is a subjective method, not based on measurable parameters; insufficient phlebographic technique may result in unsafe diagnosis; the selection of patient material may vary in different investigations; variations in thrombosis incidence may vary with the age of the patient and with the season; the incidence of thrombosis varies within the postoperative period.