The role of two noninvasive tests in deep venous thrombosis.

A prospective study was performed to evaluate the accuracy and usefulness of two noninvasive modalities, Doppler ultrasonography and segmental air plethysmography, in the detection of deep vein thrombosis. Over a two-year period, 211 limbs were studied among 167 patients, and the results were compared with venography. Doppler ultrasonography was found to be very accurate in detecting above-knee thrombi (sensitivity: 92.4%, specificity: 90.7%) while plethysmography was found to be much less accurate (sensitivity: 77.3%, specificity: 62.4%). The results were also assessed according to the mode of patient presentation. Doppler ultrasonography was found to be very useful in symptomatic out-patients, because of the lower incidence of calf thrombi, and less accurate in symptomatic inpatients and in high risk in-patients being screened. The clinical usefulness of noninvasive detection of venous thrombosis is discussed with regard to the incidence of disease and the site of thrombosis in different patient groups under study, and recommendations are made based on these results.