Clinical Policy: Critical Issues in the Evaluation
and Management of Adult Patients Presenting
With Suspected Lower-Extremity Deep Venous
Thrombosis
February 18, 2003

I. Can lower-extremity DVT be excluded by a negative D-dimer?

Level B recommendations. In patients with low clinical
probability for lower-extremity DVT, the following test
results can be used to exclude DVT:
1. A negative quantitative D-dimer assay result (turbidimetric
or ELISA) for exclusion of proximal* and
distal** lower-extremity DVT.
2. A negative whole blood D-dimer assay result in
conjunction with the Wells et al scoring system for
exclusion of proximal* and distal** DVT.
3. A negative whole blood D-dimer assay result for
exclusion of proximal* lower-extremity DVT.
Patients with a moderate-to-high risk of lower extremity
DVT cannot have DVT excluded by a single
negative D-dimer test.

II. Can lower-extremity DVT be excluded by normal findings on
a venous ultrasonographic scan?

Level B recommendations. In patients with low clinical
probability for lower-extremity DVT, negative findings
on a single venous ultrasonographic scan in symptomatic
patients excludes proximal* lower-extremity
DVT and clinically significant distal** lower-extremity
DVT. In patients with moderate to high pretest probability
of lower-extremity DVT, serial*** ultrasonographic
examinations need to be performed. Patients with high
suspicion of pelvic or inferior vena cava thrombosis
may require additional imaging technique.

III. What are the indications for fibrinolytic therapy in lower extremity
DVT?

Level C recommendations: Consider fibrinolytic therapy
in patients with limb-threatening thrombosis of the
iliofemoral system in whom the benefits of treatment
outweigh the risks of serious bleeding complications.

*Proximal lower-extremity DVT is defined as DVT from the knee to the
inguinal ligament.
**Distal lower-extremity DVT is defined as DVT isolated to calf.
***Serial venous ultrasonographic examinations refers to scheduling a patient
for follow-up ultrasonographic examination within 5 to 7 days or referral of
the patient to a primary care physician for follow-up management.