TIMI Risk Score Calculator for UA/NSTEMI

How to calculate and interpret the TIMI score for UA/NSTEMI

Who the classic TIMI score was built for

The derivation and test analysis used 1,957 TIMI 11B participants assigned to unfractionated heparin; patients presented within 24 hours of an episode of unstable angina or NSTEMI at rest and met the trial's qualifying ACS evidence. Validation included ESSENCE cohorts. These were selected trial populations, not an unselected office or emergency-department chest-pain population, and the original report cautioned that transfer to generic first-presentation chest pain required further evaluation. Use an emergency diagnostic pathway—not this score alone—when the task is to establish or exclude ACS. [1, 3]

The five CAD risk factors are source-defined

The TIMI criterion counts family history of CAD, hypertension, hypercholesterolemia, diabetes, and current smoking. Structured mode requires an explicit answer for all five and awards one TIMI point at three or more. Documented mode records only whether the complete TIMI criterion is already established. Obesity, CKD, former smoking, male sex, and other vascular history are not silently added to this particular item. [1, 7]

Why aspirin use adds one point

Recent aspirin use was one of the seven prognostic variables identified in the derivation cohort. Its point does not mean aspirin causes harm or should be stopped, and the software does not substitute clopidogrel, other antiplatelets, or anticoagulants for this historical variable. Current antiplatelet decisions are separate from this score. [1, 4]

Historical event rates and modern hs-cTn practice

The percentages came from 1990s trial populations and treatment. Contemporary case mix, high-sensitivity troponin assays, serial changes, revascularization, and antithrombotic care differ, so absolute event frequency may differ substantially. The binary cardiac-marker point does not calculate an assay cutoff, delta, 0/1-hour or 0/2-hour algorithm, or current MI diagnosis. [1, 5, 6]

TIMI, HEART, and GRACE answer different questions

HEART addresses appropriately selected undifferentiated adult emergency chest pain or suspected ACS. This TIMI page addresses the simpler seven-item UA/NSTEMI prognostic task and returns the original 14-day composite-event bin. GRACE uses more granular hemodynamic, laboratory, Killip-class, arrest, ECG, and biomarker inputs and supports broader established-ACS prognosis and model-specific horizons. The scores do not convert into one another. [1, 4, 5]

TIMI UA/NSTEMI is not TIMI STEMI or TIMI flow grade

TIMI STEMI is a separate weighted model with different predictors and a 30-day all-cause-mortality outcome. TIMI flow grade is an angiographic coronary-perfusion scale from 0 to 3; corrected TIMI frame count is another angiographic metric. None is calculated here. [7, 8]

Current guideline boundary

The 2025 ACC/AHA ACS guideline continues to describe TIMI and GRACE as validated, potentially useful ACS risk-stratification scores while emphasizing that risk scores are not diagnostic and that routine use itself has not been proven to reduce cardiovascular events. The 2023 ESC pathway prioritizes ECG, clinical assessment, accelerated hs-cTn algorithms, and uses GRACE >140 in an invasive-risk context. This page therefore does not translate any TIMI total into an invasive-strategy or medication instruction. [4, 5, 6]

There is no universal “normal” TIMI score

Zero is the minimum, not zero risk or a normal finding. The original report combined scores 0 and 1 and observed 4.7% for the composite endpoint in that test cohort. The model's reported test-cohort C statistic was about 0.65: simplicity is its strength, not maximal discrimination. [1, 2]

Important emergency limits

Do not delay emergency evaluation for STEMI or an equivalent, ongoing high-risk symptoms, shock, acute heart failure, significant arrhythmia, or another urgent condition to complete this score. No score here establishes or excludes NSTEMI, authorizes discharge, or chooses treatment. [4, 5]