Duke Treadmill Score Calculator (Exercise Stress Test Prognosis)
Calculate the Duke Treadmill Score from Bruce protocol exercise time, maximum ST deviation and the angina index — with low, moderate or high risk group, annual mortality and four-year survival.
How it works
DTS = exercise time (minutes, Bruce protocol) − 5 × maximum ST deviation (mm) − 4 × angina index (0 none, 1 non-limiting, 2 exercise-limiting). Low risk ≥ +5 · moderate −10 to +4 · high ≤ −11.
The Duke Treadmill Score (Mark et al., Annals of Internal Medicine 1987 and New England Journal of Medicine 1991) turns an exercise ECG into a prognostic number. In outpatients with suspected coronary disease, about two-thirds had low-risk scores with 99% four-year survival (0.25% annual mortality), while the 4% with high-risk scores had 79% four-year survival (about 5% a year) and are usually referred for coronary angiography. It applies to the Bruce protocol; ST deviation is the largest net change in any lead except aVR.
Worked example
A patient exercises for 9 minutes on the Bruce protocol, develops 1.5 mm of ST depression and non-limiting angina: DTS = 9 − 5 × 1.5 − 4 × 1 = 9 − 7.5 − 4 = −2.5 — moderate risk (−10 to +4), about 1.25% annual mortality.
Sources: Mark DB et al. Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med 1991 · Mark DB et al. Exercise treadmill score for predicting prognosis in coronary artery disease. Ann Intern Med 1987
Frequently asked questions
What is a good Duke Treadmill Score?
A score of +5 or more is low risk, with about 0.25% annual mortality. Scores from −10 to +4 are moderate risk and −11 or lower are high risk.
What is the angina index?
0 if there was no angina during the test, 1 if angina occurred but did not stop the test, and 2 if angina was the reason the test was stopped.
Can I use it with a protocol other than Bruce?
The score was derived with the Bruce protocol. With other protocols, exercise time is not equivalent; converting to Bruce minutes via METs is sometimes done but is less validated.
What happens after a high-risk score?
High-risk patients (≤ −11) are usually referred for coronary angiography; moderate-risk patients often have stress imaging to refine the risk.
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Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.