No abstract

The diagnostic accuracy of Doppler ultrasound, impedance plethysmography, activated thrombelastography (TEG), and fibrin split products (FSP) assays were compared to the results of ascending venography in 127 consecutive patients with suspected deep venous thrombosis (DVT). The combination of Doppler with impedance plethysmography was 96% accurate in predicting normal limbs and 83% accurate in identifying limbs harboring thrombi. This combination of flow tests was more sensitive in detecting clots at the popliteal level or above (15/17 88%) than in the calf veins (18/23 78%). The coagulation tests had a high percentage of false positive results (TEG - 39%; FSP - 52%). TEG and FSP combined were 79% (67/87) accurate in normal limbs; 72% (29/40) accurate in those with thrombosis. 0/87 patients had all four tests positive in the face of a normal venogram. 1/40 patients with thrombosis had normal results with all four tests. This patient only had calf clots.These results suggest that the addition of blood tests to flow studies does improve sensitivity and specificity when all tests are either positive or negative. The presence of normal blood tests and flow studies completely excluded thrombi in this series.