Deep vein thrombosis: patients at low-risk on a clinical diagnosis rule with a normal d-dimer were unlikely to have one

Clinical bottom line (level 4)

  1. Patients at low-risk for a deep vein thrombosis on a clinical prediction rule with a normal d-dimer were unlikely to have a DVT (LR + 0.039) .
Kearon et al: Ann Intern Med 2001; 135 : 108-111
Expires May 2004

The study

Setting: thromboembolism service, 3 university hospitals, Canada

445 patients (aged mean 60, 64% female) with a first suspected deep vein thrombosis

Excluded if
  • aged < 18
  • contraindication to contrast media
  • geographic inaccesibility
  • suspected upper extremity deep vein thrombosis
  • no symptoms within 48 hours of presentation
  • treated with anticoagulants for 72 hours or more
  • life-expectancy < 3 months


Independent ?blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • Patients considered at low-risk and with a normal d-dimer were followed for 3 months. All other patients received venous ultrasonography and impedance plethysmography. Discordant results or high-risk with a normal d-dimer led to a venogram. Normal results on ultrasound and IPG led to serial scanning and no anticoagulation.
Diagnostic test: Clinical prediction rule developed by Wells et al and d-dimer

The evidence

pre-test probability of deep vein thrombosis: 13%, (95% CI: 9.7% to 16%)

diagnostic test DVT no DVT LR
(95% CI)		 post-test probability
high-risk and abnormal d-dimer 33 41 5.6
(3.8 to 8.1) 		45%
high-risk and normal d-dimer 2 8 1.7
(0.38 to 8.0) 		20%
moderate-risk and abnormal d-dimer 17 68 1.7
(1.1 to 2.7) 		20%
moderate-risk and normal d-dimer 7 120 0.40
(0.20 to 0.83) 		6%
low-risk and abnormal d-dimer 4 29 0.95
(0.35 to 2.6) 		12%
low-risk and normal d-dimer 1 177 0.039
(0.0056 to 0.27) 		0.6%
total 64 443

Citation

  1. Kearon C, Ginsberg JS, Douketis D, et al: management of suspected deep venous thrombosis in outpatients by using clinical assessment and d-dimer testing. Ann Intern Med 2001; 135 : 108-111
Search Terms:
Contributor: Chris Ball, May 2002
Reviewer:

Clinical Question.
Patient first suspected DVT
Intervention or Exposure clinical diagnosis rule and d-dimer
Outcome deep vein thrombosis