Twenty six patients (without thrombosis) had a normal 125I-fibrinogen test, among whom 15 had a normal phlebography; 18 patients (with thrombosis) had a positive 125I-fibrinogen test among whom 11 had a positive phlebography. There was a discrepancy between phlebography and 125I-fibrinogen test in 2 patients. In patients with thrombosis, there is a significantly increase of FgE levels for several days after the intervention. However the measurement of FgE is not a reliable test (4% of false positive and 38% of false negative); but it is always elevated in femoral and popliteal thrombosis.