Revised Trauma Score (RTS) Calculator

Code GCS, systolic pressure and respiratory rate 0 to 4 each, then read both forms: the coded sum from 0 to 12 and the weighted value from 0 to 7.8408. They are different numbers and TRISS consumes the weighted one.

Last updated 8 Oct 2026

Revised Trauma Score

Three coded variables to 0–7.8408

Glasgow Coma Scale totalThe first recorded total, 3 to 15. The RTS uses the TOTAL and not the components. An intubated or paralysed patient has no valid total at all — see the Glasgow Coma Scale calculator and its NT rule — and substituting 1 for an untestable component understates the coded value and so the whole score.

Systolic blood pressure (mmHg)The first recorded value. Enter 0 for no obtainable blood pressure, which codes 0 — distinct from an unrecorded value, which cannot be scored. The thresholds are 89, 76 and 50, and note that the top band is published as greater than 89 rather than 90 or above.

Respiratory rate (per minute)This item is not monotonic. 10 to 29 codes 4, and a rate above 29 codes 3 — so tachypnoea scores the same as a rate of 6 to 9. A patient breathing 34 is penalised and a patient breathing 29 is not, for one breath.

5.8806weighted RTSExample

GCS 10, systolic 80 mmHg, respiratory rate 32 per minute

Formula

Coded RTS = GCS code + systolic code + respiratory code (0 to 12)
Weighted RTS = 0.9368 × GCS code + 0.7326 × systolic code + 0.2908 × respiratory code (0 to 7.8408)

two forms, two scales: the coded form sums three 0 to 4 values for a 0 to 12 integer; the weighted form applies the published coefficients for a continuous 0 to 7.8408. The maximum is 4 × (0.9368 + 0.7326 + 0.2908) = 7.8408 exactly. A patient coded 4, 4, 4 scores 12 one way and 7.8408 the other, and neither is a version of the other
which form TRISS uses: the weighted one. The North Carolina trauma registry data dictionary names its field “RTS (WEIGHTED)” and gives the formula as 0.9368 GCS + 0.7326 SBP + 0.2908 RR. Substituting the coded total into TRISS would put a value of up to 12 into a term whose domain stops at 7.8408, and the survival probability returned would be nonsense
the weights: 0.9368 for the GCS code, 0.7326 for systolic pressure, 0.2908 for respiratory rate, published in the 1989 revision of the Trauma Score by Champion and colleagues and derived from Major Trauma Outcome Study data. Read here from the North Carolina registry data dictionary and confirmed arithmetically: multiplying the later MTOS blunt RTS coefficient of 0.8085 by each of these three weights reproduces the component coefficients 0.2351, 0.5923 and 0.7574 published independently in Yonsei Medical Journal, to four decimal places
the respiratory item is not monotonic: 10 to 29 codes 4; above 29 codes 3; 6 to 9 codes 2; 1 to 5 codes 1; apnoea codes 0. So a rate of 34 and a rate of 8 score the same, and 29 and 30 differ by a code
what it is for, and is not: a physiological snapshot at first contact, built to stratify and compare populations and to feed outcome models. It says nothing about anatomy — a patient with a normal RTS can have an ISS of 34 — and it is measured once, so it cannot show a deterioration. Sedation, intoxication, paralysis, intubation and a pre-existing neurological deficit all corrupt the GCS term

Worked example

GCS 10, systolic 80 mmHg, respiratory rate 32 per minute
GCS 10 falls in 9 to 12, so the GCS code is 3
Systolic 80 falls in 76 to 89, so the systolic code is 3
Respiratory rate 32 is above 29, so the respiratory code is 3 — the same code a rate of 8 would get
Coded total = 3 + 3 + 3 = 9 points out of 12
Weighted = 0.9368(3) + 0.7326(3) + 0.2908(3) = 2.8104 + 2.1978 + 0.8724 = 5.8806 out of 7.8408
9 and 5.8806 are the same patient. The TRISS page refuses an RTS above 7.8408 outright, so 9 cannot be entered there — but a calculator without that range check would return 99.1 per cent modelled survival for the worked case instead of 85.2, and that is the entire reason this page prints both forms
Drop the respiratory rate to 29 and the code rises to 4: weighted 6.1714, coded 10. One breath per minute

Coded values, 0 to 4

Read off the LOINC answer lists for the Revised Trauma Score (LL7025-1 for the GCS, LL7026-9 for systolic pressure) and cross-checked against table 1 of a 2017 BMC Surgery comparison. Note the respiratory column: the code-4 row is a band in the middle, not the top, so the item runs up and then down. Note also that the systolic top band is greater than 89 rather than 90 or above, which is the same thing for integers and is not the same thing for a documented 89.5.
Code	Glasgow Coma Scale	Systolic BP (mmHg)	Respiratory rate (per minute)
4	13 – 15	greater than 89	10 – 29
3	9 – 12	76 – 89	greater than 29
2	6 – 8	50 – 75	6 – 9
1	4 – 5	1 – 49	1 – 5
0	3	0	0

The two forms at the extremes and in between

Every weighted figure is this calculator’s own arithmetic. The two columns coincide only at 0. The ratio between them is constant at 0.6534 only when all three codes are equal, as in the rows above — for any mixed set it is not, which is why there is no conversion from one form to the other.
Codes (GCS, systolic, respiratory)	Coded total	Weighted RTS
4, 4, 4 — physiologically normal	12	7.8408
3, 3, 3 — the worked example	9	5.8806
4, 4, 3	11	7.5500
2, 2, 2	6	3.9204
1, 1, 1	3	1.9602
0, 0, 0 — no response, no pressure, apnoeic	0	0.0000

Two numbers, one patient, and the error that follows

The Revised Trauma Score reduces the first recorded physiology to three coded values: the Glasgow Coma Scale total, the systolic blood pressure and the respiratory rate, each mapped onto 0 to 4. It replaced the 1981 Trauma Score, which had included capillary refill and respiratory effort, and the 1989 revision dropped those two because they could not be measured reliably in the field. The coded values are then used in one of two ways, and this is where almost all of the confusion in this area comes from.

Added together, the three codes give an integer from 0 to 12. Multiplied by the published coefficients 0.9368, 0.7326 and 0.2908 and then added, they give a continuous value from 0 to 7.8408. The weights are not arbitrary: they came out of Major Trauma Outcome Study data and they say that the neurological item carries roughly three times the information of the respiratory item. The two forms are not versions of one another and there is no conversion between them — the ratio depends on which item is abnormal. A patient coded 3, 3, 3 scores 9 one way and 5.8806 the other.

Which form matters depends on what the number is for. The coded total is the field most pre-hospital triage schemes were written around. The weighted value is what goes into the TRISS survival model, and substituting the coded total there puts a number of up to 12 into a term whose domain stops at 7.8408; on this page’s own worked example that mistake moves the modelled survival probability from 85 per cent to above 99.

Two further things decide whether the score means anything. The respiratory item is not monotonic — 10 to 29 codes 4 but anything above 29 codes 3, the same as a rate of 6 to 9 — so a compensating, tachypnoeic patient is penalised for compensating. And the GCS term requires a valid GCS total, which an intubated, sedated or paralysed patient does not have; entering 1 for an untestable component drags the coded value and the whole score down. The RTS is physiology at one moment, says nothing about anatomy, and cannot show a trend. It is a comparison tool and a model input, and the published cut-points built on it are triage decisions that this page deliberately does not render.

Frequently asked questions

What is the difference between the coded and weighted RTS?

The coded RTS is the three 0 to 4 values simply added, giving 0 to 12. The weighted RTS multiplies the same three codes by 0.9368, 0.7326 and 0.2908 and adds them, giving 0 to 7.8408. They are different numbers for the same patient and there is no conversion between them, because the ratio depends on which item is abnormal.

Which RTS does TRISS use?

The weighted one. The TRISS logistic model carries a coefficient on a term whose range is 0 to 7.8408. Feeding it a coded total of up to 12 inflates the modelled survival probability badly — on this page’s worked example, from 85 per cent to above 99.

Why does a respiratory rate of 35 score less than a rate of 20?

Because the item is deliberately not monotonic: 10 to 29 codes 4, and anything above 29 codes 3, the same code as a rate of 6 to 9. Both tachypnoea and bradypnoea are abnormal. The practical consequence is that a patient compensating for shock by breathing fast loses 0.2908 of weighted score for it.

What is the maximum Revised Trauma Score?

12 coded, or 7.8408 weighted — which is 4 multiplied by the sum of the three coefficients, 0.9368 plus 0.7326 plus 0.2908. The minimum of both forms is 0, reached by a patient with GCS 3, no obtainable blood pressure and no respiratory effort.

Can I calculate an RTS on an intubated patient?

Not reliably, because there is no valid GCS total once a component is untestable. Recording the verbal component as 1 rather than not testable understates the GCS, which may drop the GCS code and remove up to 0.9368 from the weighted score. The same caveat applies to sedation, paralysis and a pre-existing neurological deficit.

Related calculators

References

Regenstrief Institute. LOINC answer list LL7025-1, Revised Trauma Score — Glasgow coma scale. loinc.org/LL7025-1
Regenstrief Institute. LOINC answer list LL7026-9, Revised Trauma Score — Systolic blood pressure. loinc.org/LL7026-9
North Carolina Office of Emergency Medical Services. North Carolina Trauma Registry Data Dictionary — the weighted RTS field. info.ncdhhs.gov/dhsr/EMS/trauma/pdf/datadictionary.pdf
Table 1, Revised Trauma Score and New Trauma Score coded values, BMC Surgery 2017. doi:10.1186/s12893-017-0272-4
Wagh A, Subhedar A, Mujawar P. Evaluation of trauma outcomes using the trauma and injury severity score at a tertiary care centre: a prospective observational study. Int Surg J. 2026;13(10):1947–51.

Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/