RACE scale: how the Rapid Arterial oCclusion Evaluation is scored

The RACE scale adds five stroke examination items (facial palsy, arm motor, leg motor, head and gaze deviation, and a cortical sign) to a total from 0 to 9. A total of 5 or more sets the flag lvo_suggested to true.

Not a medical device. Not a diagnosis or dosing recommendation.

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Pérez de la Ossa N et al. · 2014
The RACE scale formula
Worked examples
Frequently asked questions

What is the RACE scale?

RACE stands for Rapid Arterial oCclusion Evaluation. Natalia Pérez de la Ossa and colleagues published it in Stroke in 2014 as a short scale for use before a patient reaches hospital. It aims to pick out strokes that may come from a large vessel occlusion (LVO), a blockage in one of the large arteries of the brain.

The name has nothing to do with a person's race or ethnicity. It's an acronym, and none of its inputs is about race.

Magent's calculator adds the five item points you assign, returns the total out of 9, and sets lvo_suggested to true at 5 or more, the cutoff from the paper. It doesn't examine anyone; every item comes from the person entering the scores.

This page explains the scoring. It doesn't say what a score means for a particular person.

The RACE scale formula

RACE = facial palsy        0 absent · 1 mild · 2 moderate to severe
     + arm motor           0 normal to mild · 1 moderate · 2 severe
     + leg motor           0 normal to mild · 1 moderate · 2 severe
     + head/gaze deviation 0 absent · 1 present
     + cortical sign       0 to 2 (aphasia if right-sided weakness, agnosia if left)
total 0 to 9 · lvo_suggested = true if total is 5 or more

Exact expression the calculator uses:

RACE = facial_palsy (0 absent, 1 mild, 2 moderate to severe) + arm_motor (0 normal to mild, 1 moderate, 2 severe) + leg_motor (0 normal to mild, 1 moderate, 2 severe) + gaze_deviation (0 absent, 1 present) + cortical (0–2; aphasia if right hemiparesis, agnosia if left); Pérez de la Ossa 2014 Table 1; max 9; lvo_suggested if score ≥ 5

Inputs

Input	Meaning	Accepted range
`facial_palsy`	0 absent, 1 mild, 2 moderate to severe	0, 1 or 2
`arm_motor`	0 normal to mild, 1 moderate, 2 severe	0, 1 or 2
`leg_motor`	0 normal to mild, 1 moderate, 2 severe	0, 1 or 2
`gaze_deviation`	Head and gaze deviation: 0 absent, 1 present	0 or 1
`hemiparesis_side`	Side of the weakness; sets which cortical sign is scored	right or left
`cortical`	Aphasia (right) or agnosia (left): 0 both tasks done, 1 one, 2 neither	0, 1 or 2

How the scoring works

Score each motor item: facial palsy, arm motor and leg motor are 0 to 2 each.
Score head and gaze deviation: 0 if absent, 1 if present.
Pick the cortical sign from the side of weakness.

- Right-sided weakness → aphasia. The person is asked to close their eyes and make a fist. Both done = 0, one = 1, neither = 2. - Left-sided weakness → agnosia. The person is asked to recognize their arm and their impairment. Both = 0, one = 1, neither = 2.

Add the five items. The total runs from 0 to 9.
Flag: lvo_suggested is true when the total is 5 or more, false otherwise.

The side doesn't change the number of points. It decides which cortical task the points describe.

Inputs and output

Every item is a whole number you assign, and hemiparesis_side is the word right or left. A value outside its range, or a side other than right or left, is rejected with an error. The calculator returns each item, the total, the maximum of 9, the side and lvo_suggested. It doesn't return sensitivity or other test statistics.

Worked examples

These use Magent's own expected values for the calculator.

Example 1: all items 0, right-sided weakness

0 + 0 + 0 + 0 + 0 = 0 out of 9.
0 is below 5 → lvo_suggested false.

Example 2: facial palsy 2, arm motor 2, gaze deviation 1

Leg motor 0 and cortical 0.
2 + 2 + 0 + 1 + 0 = 5.
5 meets the cutoff → lvo_suggested true.

Example 3: every item at its maximum

2 + 2 + 2 + 1 + 2 = 9, the maximum.
lvo_suggested true.

Example 4: cortical 2 alone, either side

All other items 0, cortical 2.
Total 2 with right-sided weakness (aphasia path) and 2 with left-sided weakness (agnosia path). The side changes the task, not the points.
lvo_suggested false.

History of the RACE scale

The calculator cites Pérez de la Ossa N, Carrera D, Gorchs M and colleagues, Stroke, 2014 (volume 45, issue 1, pages 87–91). Their abstract describes building the scale from the items of the NIH Stroke Scale that were most predictive of a large vessel occlusion in a retrospective group of patients. The scale was then tested prospectively in the field, where trained medical emergency technicians applied it. The item points come from Table 1 of the paper, and the abstract reports results for a cutoff of 5.

When it's used

The 2014 paper describes the RACE scale as a prehospital tool, applied in the field to people with a suspected acute stroke.

Where it's used

The paper's setting was emergency medical services in the field, before arrival at a hospital. The five items are bedside observations with no lab values or imaging.

Who uses it

In the paper, trained medical emergency technicians scored the scale. With this calculator, the person entering the item points assigns them; the calculator adds them and applies the cutoff.

Limits of the calculation

The calculator doesn't examine anyone. Every item point is assigned by the person entering it.
lvo_suggested reflects a cutoff of 5. It isn't imaging and doesn't confirm or rule out an occlusion.
It doesn't return sensitivity, predictive values or other test statistics.
It isn't an order to move a patient to a particular hospital.
This page doesn't say what to do with a score.

Clinical decisions belong to a qualified clinician who knows the patient.

NIHSS is the full NIH Stroke Scale from Brott and colleagues. The RACE items were drawn from it.
LAMS sums facial droop, arm drift and grip.
FAST-ED is another field triage scale built from stroke examination items.

Glossary

LVO: large vessel occlusion, a blockage of one of the large arteries supplying the brain.
Hemiparesis: weakness on one side of the body.
Aphasia: a language disturbance; scored here with right-sided weakness.
Agnosia: failure to recognize; scored here with left-sided weakness, as not recognizing the arm or the impairment.
Gaze deviation: the head and eyes turned to one side.

Common mistakes

Taking the name literally. RACE is an acronym, not a race-based equation.
Scoring both cortical signs. Score aphasia with right-sided weakness or agnosia with left, not both.
Giving gaze deviation 2 points. It's 0 or 1.
Reading the flag as a result from imaging. It reflects the cutoff of 5.

Source

Pérez de la Ossa N, Carrera D, Gorchs M, et al. Design and validation of a prehospital stroke scale to predict large arterial occlusion: the rapid arterial occlusion evaluation scale. Stroke. 2014;45(1):87-91. DOI: 10.1161/STROKEAHA.113.003071. PMID: 24281224

Frequently asked questions

How is the RACE scale scored?

Add facial palsy (0 to 2), arm motor (0 to 2), leg motor (0 to 2), head and gaze deviation (0 or 1) and a cortical sign (0 to 2). The total runs from 0 to 9.

What RACE score suggests a large vessel occlusion?

5 or more. At that total the calculator sets lvo_suggested to true.

No. RACE stands for Rapid Arterial oCclusion Evaluation, and race isn't an input.

Why does the side of weakness matter?

It decides which cortical sign is scored: aphasia with right-sided weakness, agnosia with left. The points range is the same either way.