Background. Because of the rapid growth in requests for lower extremit
y venous duplex ultrasonographic examinations, we have evaluated test
results to determine the approximate indications for testing and wheth
er there is overuse of this technique. Methods. We reviewed the record
s of all patients who had duplex ultrasonogram during an 18-month peri
od to rule out deep vein thrombosis (DVT). Test outcome was evaluated
with data on the age, gender, outpatient or inpatient status, duration
of symptoms, physical findings, and risk factors of the patients. Res
ults. We reviewed 3474 examinations; 1265 outpatients and 1231 inpatie
nts were evaluated to rule wt DVT, and 978 patients were evaluated to
rule out a source of pulmonary embolism. More outpatients were female,
and they tended to be younger; outpatients also had more acute femoro
popliteal DVT. The presence of sudden onset of unilateral swelling was
a strong predictor of acute DVT in all three groups: 52% of such pati
ents were found to have DVT. Mild unilateral symptoms with a. coexiste
nt risk factor was associated with a 10% to 20% prevalence of acute DV
T. Chronic unilateral swelling was associated with acute DVT only with
a coexistent risk factor and only in 1% of such patients. Bilateral s
welling was only associated with acute DVT in the inpatient population
, with 17% of studies having positive results. If calf tenderness was
the only symptom with no associated risk factors, seven (1.6%) of 415
patients had acute DVT and six of these were tibioperoneal. No patient
s with cellulitis or isolated joint pain had acute DVT. With clinicall
y suspected pulmonary embolism in patients without associated symptoms
or risk factors, 7 (1.5%) of 447 studies showed tibioperoneal disease
with no acute femoropopliteal disease. Conclusions. The physical exam
ination and clinical history of the patient re-main important indicato
rs Of the presence (or absence) of lower extremity DVT and can guide t
he appropriate use of duplex ultrasonography for the diagnosis.