How this instrument works
This score starts by coding three raw measurements onto a shared 0-to-4 scale: Glasgow Coma Scale, systolic blood pressure, and respiratory rate each get their own band table, so a GCS of 14 and a systolic pressure of 100 land on the same footing before anything is combined. Those three coded values are then multiplied by fixed weights and added together: 0.9368 for GCS, 0.7326 for systolic pressure, and 0.2908 for respiratory rate, producing a decimal figure that tops out at 7.8408 for a fully normal patient and bottoms out at 0 for someone with no measurable response on any of the three.
Those particular weights are not a stylistic choice — they come out of a logistic regression model Champion and colleagues fit to a large trauma outcomes database, published in 1989 as a revision of the original 1981 Trauma Score. The regression estimated how strongly each vital sign predicted survival independent of the other two, and the resulting weights reflect what it found: impaired consciousness, captured by GCS, was the single strongest independent predictor among the three, blood pressure came next, and respiratory rate contributed the least. That ranking is why GCS carries roughly three times the weight of respiratory rate in the final sum, rather than the three inputs simply being added unweighted.
A related but different tool shares nearly the same name and causes real confusion: the Triage RTS, or T-RTS, uses the same three band tables but skips the weighting entirely, just adding the coded values for a whole-number range of 0 to 12. Field triage favors T-RTS because addition is fast under pressure and needs no calculator; the weighted version built here trades that speed for the added precision the regression weights provide, and is the version generally meant when a paper or chart simply says RTS without qualifying which one. Mixing the two up — quoting a T-RTS total as if it were this weighted figure, or the reverse — produces numbers that look plausible but aren't actually comparable.
- Enter Glasgow Coma Scale (3-15) from the current exam.
- Enter Systolic blood pressure in mmHg.
- Enter Respiratory rate in breaths per minute.
- Read the three coded values (0-4 each) and the weighted RTS total, which runs from 0 to 7.84.
Worked example — a fully normal RTS of 7.8408
A GCS of 15, a systolic pressure of 120, and a respiratory rate of 16 each code to the top band of 4. The weighted sum runs 0.9368×4 + 0.7326×4 + 0.2908×4 = 3.7472 + 2.9304 + 1.1632 = 7.8408 — the maximum figure a fully normal patient can register.
A more compromised patient shows the same arithmetic at a lower band. A GCS of 6, a systolic pressure of 60, and a respiratory rate of 8 each code to 2, giving 0.9368×2 + 0.7326×2 + 0.2908×2 = 1.8736 + 1.4652 + 0.5816 = 3.9204. Push every input to its worst extreme instead — no eye, verbal, or motor response for a GCS of 3, no measurable blood pressure, and no respiratory effort — and all three code to 0, so every term in the sum is zero and the total reads 0.0, the floor of the scale.
Questions
Why do GCS, blood pressure, and respiratory rate get different weights?
Because Champion and colleagues derived the weights from a logistic regression model of survival fit to a large trauma database, not from a judgment call about which vital sign feels most important. The regression found Glasgow Coma Scale was the strongest independent predictor of survival among the three, blood pressure came next, and respiratory rate contributed the least — and the weights, 0.9368, 0.7326, and 0.2908 respectively, are sized to match that ranking.
What is the difference between RTS and Triage RTS (T-RTS)?
Both use the same three band tables to code GCS, systolic pressure, and respiratory rate onto a 0-4 scale, but T-RTS simply adds the three coded values for a whole-number total from 0 to 12, built for speed in field triage. This calculator computes the full weighted figure, multiplying each coded value by its survival-model weight before summing — more precise, but requiring the multiplication that field triage skips. The two aren't interchangeable, and a total quoted as one shouldn't be read as the other.
Can the Revised Trauma Score be calculated from a field assessment?
Yes — all three inputs, GCS, systolic blood pressure, and respiratory rate, are things a paramedic or emergency clinician can obtain without lab work or imaging, which is part of why the tool has stayed in wide use since 1989. In practice, field teams under real time pressure often reach for the simpler, unweighted T-RTS instead, saving the weighted version for retrospective outcome studies and hospital-based scoring.
What does a low RTS score indicate?
A lower reading reflects worse derangement in one or more of the three vital signs feeding it, and figures well below the maximum of 7.8408 are associated with substantially higher mortality risk in the trauma outcomes literature the tool was built from. It is used alongside injury severity measures and patient age in combined outcome models like TRISS, rather than read alone as a full prognosis.
Why is the maximum RTS 7.8408 instead of a round number like 12?
Because the calculation multiplies each of the three coded values, all at their maximum of 4, by decimal weights that sum to 1.9602 rather than 1: 0.9368 + 0.7326 + 0.2908. Four times that combined weight gives 7.8408. It is the Triage RTS, which skips the weighting, that produces the round maximum of 12.
References
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.