Table 1.
Summary of prehospital stroke severity tools
| ACT-FAST1 | CG-FAST2 | CPSS2 | C-STAT2 | FAST-ED3 | FAST-PLUS2 | G-FAST2 | LAMS2 | PASS2 | RACE2 | |
|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||
| No. of items assessed | 3 | 5 | 3 | 3 | 5 | 4 | 4 | 3 | 3 | 6 |
| Face weakness | x | x | x | x | x | x | x | |||
| Arm weakness | x | x | x | x | x | x | x | x | x | x |
| Leg weakness | x | x | ||||||||
| Grip strength | x | |||||||||
| Gaze deviation | x | x | x | x | x | x | ||||
| Hemineglect | x | x | x | |||||||
| Dysarthria or Aphasia | x* | x | x | x | x | x | x | |||
| LOC questions | x | x | x | |||||||
| Standard threshold for a positive test | +/− | ≥4 | =3 | ≥2 | ≥4 | +/− | ≥3 | ≥4 | ≥2 | ≥5 |
| Sensitivity◆ | 0.76 | 0.50 | 0.57 | 0.50 | 0.60 | 0.60 | 0.67 | 0.63 | 0.59 | 0.67 |
| Specificity◆ | 0.82 | 0.89 | 0.85 | 0.85 | 0.85 | 0.83 | 0.82 | 0.84 | 0.83 | 0.87 |
| Probability of LVO after a positive test (PPV)◆ with a baseline: | ||||||||||
| 5% LVO prevalence | 18% | 19% | 17% | 15% | 17% | 16% | 16% | 17% | 15% | 21% |
| 10% LVO prevalence | 32% | 34% | 30% | 27% | 31% | 28% | 29% | 30% | 28% | 36% |
| 15% LVO prevalence | 43% | 45% | 40% | 37% | 41% | 38% | 40% | 41% | 38% | 48% |
| 20% LVO prevalence | 51% | 53% | 49% | 45% | 50% | 47% | 48% | 50% | 46% | 56% |
ACT-FAST, Ambulance Clinical Triage For Acute Stroke Treatment, CG-FAST Conveniently-Grasped Field Assessment Stroke Triage, CPSS Cincinnati Prehospital Stroke Scale, C-STAT Cincinnati Stroke Triage Assessment Tool, FAST-ED Field Assessment Stroke Triage for Emergency Destination, FAST-PLUS Face-Arm-Speech-Time plus severe arm or leg motor deficit, G-FAST Gaze-Face-Arm-Speech-Time, LAMS Los Angeles Motor Scale, PASS Prehospital Acute Stroke Severity, RACE Rapid Arterial oCclusion Evaluation, LOC level of consciousness, LVO large vessel occlusion, PPV positive predictive value, +/− scored as either positive or negative
ACT-FAST tests for language difficulty and isolated dysarthria does not count
Sensitivity, specificity, and PPV are reported at each severity tool’s standard threshold. For tools with multiple possible thresholds, lower thresholds will be more sensitive but less specific. Higher thresholds will be less sensitive but more specific
Sensitivity and specificity as noted in Zhao et al.’s study (ref. 36)
Sensitivity and specificity as noted in Duvekot et al.’s study (ref. 25)
Sensitivity and specificity as noted in Nguyen et al.’s study (ref. 26)