In order to determine the value of air plethysmography (APG) in the de
tection of acute deep vein thrombosis (DVT), the authors studied prosp
ectively 79 consecutive patients referred for suspected acute DVT. All
patients were examined with venography and APG. Venography demonstrat
ed acute DVT in 38 patients. In 8 patients the DVT was confined to the
calf and in 30 this was in the popliteal and/or more proximal veins.
Venography was negative in 41 patients. An outflow fraction value with
superficial occlusion of the long saphenous vein at the knee of less
than 28% in combination with a venous volume of less than 50 mt identi
fied all patients with acute proximal DVT. There was one false-positiv
e result. However, isolated calf vein thrombi were equally distributed
, and half of them were not detected. Air plethysmography is a reliabl
e, inexpensive, easy to perform, and accurate noninvasive test for the
diagnosis of proximal acute DVT. It may be a useful screening test wh
en there is a big demand for noninvasive tests, and relatively little
time is available on a duplex scanner.