Clinical Policy: Critical Issues in the Evaluation
and Management of Adult Patients Presenting
With Suspected Pulmonary Embolism
October 3, 2002

Wells et al criteria for assessment of pretest probability for
PE.

Suspected DVT 								3
An alternative diagnosis is less likely than PE 			3
Heart rate >100 beats/min 						1.5
Immobilization or surgery in the previous 4 wk 				1.5
Previous DVT/PE 							1.5
Hemoptysis 								1
Malignancy (on treatment, treated in the past 6 mo or palliative) 	1

		Mean Prob	% with 		Interpretation
Score Range 	of PE, % 	This Score 	of Risk
<2 points 	3.6 		40 		Low
2-6 points 	20.5 		53 		Moderate
>6 points 	66.7 		7 		High

Reprinted with permission from Wells PS, Anderson DR, Rodger M, et al. Derivation of
a simple clinical model to categorize patient’s probability of pulmonary embolism:
increasing the models utility with the SimpliRED D-dimer. Thromb Haemost.
2000;83:416-420.

Wicki et al criteria for assessment of pretest probability for
PE.

Age 60-79 			1
Age >79				2
Prior DVT/PE 			2
Recent surgery 			3
Heart rate >100 beats/min 	1
PaCO2, mm Hg
	<36 			2
	36-39 			1
PaO2, mm Hg
	<49			4
	49-60			3
	>60-71			2
	>71-82			1
Chest x-ray
	Plate-like atelectasis	1
	Elevation of 
		hemidiaphragm	1

		Mean Prob	% with		Interpretation
Score Range 	of PE, % 	This Score 	of Risk
0-4 		10 		49 		Low
5-8 		38 		44 		Moderate
9-12		81		6		High


I. Can a negative D-dimer exclude PE?

Level B recommendations. In patients with a low pretest
probability of PE, use the following tests to exclude PE:
1. A negative quantitative D-dimer assay (turbidimetric
or ELISA).
2. A negative whole blood cell qualitative D-dimer
assay in conjunction with a Wells’ score of 2 or less.

Level C recommendations. In patients with a low pretest
probability of PE, negative findings on a whole blood
D-dimer assay (when not used with Wells’ scoring system)
or immunofiltration D-dimer assay can be used to
exclude PE.

II. When can V/Q scan alone or in combination with venous
ultrasonography and/or D-dimer exclude PE?

Level A recommendations. In patients with a low-to moderate
pretest probability of PE, a normal perfusion
scan reliably excludes clinically significant PE.

Level B recommendations. In patients with a low-tomoderate
pretest probability of PE and a non-diagnostic
V/Q scan, use 1 of the following tests instead of pulmonary
arteriogram to exclude clinically significant PE:
1. A negative quantitative D-dimer assay (turbidimetric
or ELISA).
2. A negative whole blood cell qualitative D-dimer
assay in conjunction with a Wells’ score of 4 or less.
3. A negative single bilateral venous ultrasonographic
scan for low-probability patients.
4. A negative serial* bilateral venous ultrasonographic
scan for moderate-probability patients.

*Serial venous ultrasonography refers to scheduling a patient for follow-up
examination in the ED within 3 to 7 days or referring to a primary care
physician for follow-up.

Level C recommendations. In patients with a low-to moderate
pretest probability of PE and a nondiagnostic
V/Q scan, use a negative whole blood D-dimer assay
(when not used with Wells’ scoring system) or immunofiltration
D-dimer assay to exclude PE.

III. Can spiral CT replace V/Q scanning in the diagnostic
evaluation of PE?

Level B recommendations. Thin collimation spiral CT
scan of the thorax with 1- to 2-mm image reconstruction
may be used as an alternative to V/Q scan during
the diagnostic evaluation of patients with suspected PE.

Level C recommendations. Spiral CT scan of the thorax
with delayed CT venography may be used for increased
detection of patients with significant thromboembolic
disease.