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“TIMI score” is often used as if it names one tool, but it names two: a TIMI Risk Score for UA/NSTEMI (unstable angina / non-ST-elevation myocardial infarction) and a separate, differently-weighted TIMI Risk Score for STEMI (ST-elevation myocardial infarction). Both come from the Thrombolysis In Myocardial Infarction (TIMI) trial group led by Eugene Antman, both were published in 2000, and both stratify a patient’s short-term risk after acute coronary syndrome (ACS) — but they use different variables, different point ranges, and apply to different presentations. Using the wrong one, or citing a point total without specifying which score it came from, produces a meaningless number. This page covers both variants, what each one predicts, and where TIMI fits alongside the GRACE score in ACS triage.
Two different scores, one shared name
Both scores were derived by the same TIMI research group and share the same underlying logic — add up simple, readily-available clinical variables at presentation into an integer score that stratifies short-term risk — but they are not interchangeable and were validated on different patient populations.
| TIMI Risk Score for UA/NSTEMI | TIMI Risk Score for STEMI | |
|---|---|---|
| Presentation | Unstable angina / NSTEMI | ST-elevation MI |
| Number of variables | 7 | 8 |
| Score range | 0–7 | 0–14 |
| Primary outcome predicted | 14-day composite: death, (re)infarction, or urgent revascularization | 30-day mortality |
| Original derivation cohort | Pooled TIMI 11B and ESSENCE trial data (>7,000 patients) | InTIME II trial substudy |
| Published | JAMA, 2000 (Antman et al.) | Circulation, 2000 (Morrow et al.) |
TIMI Risk Score for UA/NSTEMI: the 7 factors
The UA/NSTEMI score assigns exactly one point per factor present, for a possible total of 0–7:
| Factor | Points |
|---|---|
| Age ≥65 years | 1 |
| ≥3 risk factors for coronary artery disease (family history, hypertension, hypercholesterolemia, diabetes, current smoker) | 1 |
| Known coronary artery disease (prior stenosis ≥50%) | 1 |
| Aspirin use in the prior 7 days | 1 |
| Severe anginal symptoms (≥2 episodes in the prior 24 hours) | 1 |
| ST-segment deviation ≥0.5 mm on the presenting ECG | 1 |
| Elevated serum cardiac biomarkers (troponin or CK-MB) | 1 |
Each factor is a simple yes/no present at the bedside — no calculation beyond addition, which is the point of the tool: it was designed to be usable at first patient contact, before labs fully return, and to be re-derivable by hand rather than requiring a calculator or nomogram.
What the UA/NSTEMI score predicts
In the original derivation and validation cohorts, the score showed a clear, graded relationship with the 14-day composite endpoint of all-cause mortality, new or recurrent myocardial infarction, or severe recurrent ischemia requiring urgent revascularization: patients scoring 0–1 had an event rate of roughly 5%, while patients scoring 6–7 had an event rate of roughly 41% — an eightfold-plus spread across the scale. This is a composite endpoint, not mortality alone; a high score does not mean a roughly 40% chance of dying, it means a roughly 40% chance of hitting one of the three composite events within 14 days. The score has since been validated in multiple independent NSTEMI cohorts and remains one of the most widely used bedside risk-stratification tools for that presentation, informing decisions such as early invasive versus conservative management and the intensity of antithrombotic therapy.
TIMI Risk Score for STEMI: a different, weighted scale
The STEMI variant uses eight variables, weighted (not one point each) according to their independent association with mortality in the derivation cohort, for a possible total of 0–14:
| Factor | Points |
|---|---|
| Age 65–74 years | 2 |
| Age ≥75 years | 3 |
| History of diabetes, hypertension, or angina | 1 |
| Systolic blood pressure <100 mmHg | 3 |
| Heart rate >100 bpm | 2 |
| Killip class II–IV (signs of heart failure at presentation) | 2 |
| Weight <67 kg | 1 |
| Anterior ST elevation or new left bundle branch block | 1 |
| Time to treatment >4 hours from symptom onset | 1 |
Note the age brackets sum to a maximum of 3 (not 2+3=5), since a patient falls into only one age category; the maximum achievable total across all nine rows is 14.
What the STEMI score predicts
The STEMI score predicts 30-day mortality, and the relationship is steep: mortality was under 1% among patients scoring 0, and the original derivation study described more than a 40-fold graded increase in mortality moving from the lowest to the highest score categories. A later validation study in STEMI patients treated with primary percutaneous coronary intervention (PCI) reported good discrimination for 30-day mortality (c-statistic 0.834) and confirmed the score’s prognostic value persisted through one-year follow-up. Because it was derived specifically on a fibrinolytic-era and PCI-treated STEMI population, it is not interchangeable with the UA/NSTEMI score’s variables or point scale, even though both go by the same short name.
TIMI score vs. GRACE score in ACS triage
The GRACE (Global Registry of Acute Coronary Events) score is the other major risk-stratification tool a patient-safety or quality program is likely to see referenced alongside TIMI. GRACE uses a broader set of continuous variables (age, heart rate, systolic blood pressure, serum creatinine, Killip class, cardiac arrest at admission, ST-segment deviation, and elevated cardiac markers) run through a weighted algorithm rather than simple point-counting, and it applies across the full ACS spectrum — UA, NSTEMI, and STEMI alike — rather than needing a separate version per presentation. Major ACS guideline bodies have generally favored GRACE for its stronger discrimination in predicting in-hospital and longer-term mortality, particularly for decisions about the timing of an invasive strategy in NSTEMI. TIMI’s advantage is calculation speed and simplicity: it can be tallied from memory at the bedside, which is why it remains in wide clinical and quality-reporting use even where GRACE is the guideline-preferred tool for formal risk stratification. Many chest-pain protocols and quality dashboards track both.
Why this matters for hospital patient-safety and quality programs
For infection-prevention and general patient-safety staff, TIMI itself is rarely the direct object of surveillance — but it shows up in three places a quality or risk-management program typically has to account for:
- Chest-pain and ACS protocol design. Order sets and standardized chest-pain pathways frequently embed a TIMI (or GRACE) calculation as a discrete, auditable step, so which variant is wired into the order set, and whether it’s the correct one for the documented presentation (UA/NSTEMI vs. STEMI), is a real order-set-validation question.
- Documentation and coding accuracy. Because the two scores share a name but not a point scale, a chart or quality abstraction tool that records “TIMI score: 4” without specifying which variant is ambiguous for anyone auditing it later — a 4 out of 7 (UA/NSTEMI) and a 4 out of 14 (STEMI) represent very different risk levels.
- Door-to-balloon and time-to-treatment metrics. The STEMI score’s inclusion of “time to treatment >4 hours” as a scored variable is a direct link between a hospital’s process-of-care performance (how fast a STEMI patient reaches reperfusion) and a validated mortality-risk instrument, which is a useful framing for connecting door-to-balloon quality metrics to patient outcomes in reporting.
Related bedside scoring tools
TIMI is one of several validated, point-based bedside risk scores hospitals use to standardize clinical decision-making. See also the SOFA score and qSOFA score for organ-dysfunction and sepsis risk, the Ranson Criteria for acute pancreatitis severity, and the Cincinnati Prehospital Stroke Scale for stroke-alert screening — each follows the same general pattern of converting bedside findings into an auditable, protocol-embeddable number. For the broader set of patient-safety and clinical-risk topics this page sits alongside, see the Patient Safety pillar.
Frequently asked questions
Is a TIMI score the same for every heart attack?
No. There are two distinct scores — one for UA/NSTEMI (7 factors, 0–7 points) and one for STEMI (8 weighted factors, 0–14 points) — and they are not interchangeable. A patient’s presentation (ST elevation present or absent) determines which one applies.
What is considered a high TIMI score?
For UA/NSTEMI, a score of 5–7 is generally considered high risk. For STEMI, scores in the upper range of the 0–14 scale (roughly 5 and above) are associated with a steep rise in 30-day mortality. Exact risk-category cutoffs vary slightly by source and by how a given institution’s protocol uses the score, so treat the raw point total, not a risk label alone, as the primary data point in documentation.
Is TIMI score still used, or has GRACE replaced it?
Both remain in active use. Guideline bodies have generally favored GRACE for formal risk stratification and invasive-strategy timing decisions because of its stronger statistical discrimination, but TIMI’s bedside simplicity (addable from memory, no continuous-variable lookup) keeps it in wide use in chest-pain protocols and quality reporting alongside GRACE rather than instead of it.
What does TIMI stand for?
Thrombolysis In Myocardial Infarction — originally the name of a series of clinical trials studying thrombolytic (clot-dissolving) therapy for heart attack, whose investigators later derived these risk scores from that trial data.
