What is the Modified Wells clinical scoring system for pulmonary embolism?

Updated: Dec 30, 2020
  • Author: Kamran Boka, MD, MS; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
  • Print


The AAFP/ACP guideline advocates use of the Modified Wells prediction rule for the above-specified estimation and interpretation requirements (see Table 1, below). However, the guideline notes that the Wells rule performs better in younger patients without comorbidities or a history of venous thromboembolism. Current evidence also suggests this tool is effective in pregnant patients. [9]

Moreover, the objective components of the Wells (Canadian Pulmonary Embolism Score) criteria have been shown to have little effect on the stratification power of the criteria; virtually all of the classification power is associated with a physician's subjective prejudgment of the likelihood of pulmonary embolism.

Table 1. Modified Wells Prediction Rule for Diagnosing Pulmonary Embolism: Clinical Evaluation Table for Predicting Pretest Probability of Pulmonary Embolism* (Open Table in a new window)

Clinical Characteristic


Previous pulmonary embolism or deep vein thrombosis

+ 1.5

Heart rate >100 beats per minute

+ 1.5

Recent surgery or immobilization (within the last 30 d)

+ 1.5

Clinical signs of deep vein thrombosis

+ 3

Alternative diagnosis less likely than pulmonary embolism

+ 3


+ 1

Cancer (treated within the last 6 mo)

+ 1

Clinical Probability of Pulmonary Embolism








*Reprinted from Am J Med, Vol. 113, Chagnon I, Bounameaux H, Aujesky D, et al, Comparison of two clinical prediction rules and implicit assessment among patients with suspected pulmonary embolism, pp 269-75, Copyright 2002.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!