Trauma severity scores are standardized tools used by healthcare professionals to measure the extent and seriousness of injuries sustained during traumatic events. These events can include car accidents, falls, gunshot wounds, industrial injuries, or any situation where the body is subjected to physical harm. The purpose of these scores is to help medical teams rapidly assess the condition of a trauma patient, make informed decisions about treatment, and predict the likelihood of recovery or survival.
Each scoring system evaluates different aspects of injury and physiological response. Some focus on anatomical damage (like the ISS), while others assess the body's vital signs and level of consciousness (such as the RTS). When combined, these scores can provide a clear picture of a patient's condition, helping guide the urgency and type of care they need.
In emergency and trauma care, every second counts. Trauma severity scores play a crucial role in helping medical professionals make quick and accurate decisions. By using these scores, healthcare providers can:
These scoring systems ensure consistency in trauma assessment, reduce errors in decision-making, and improve communication between emergency departments, trauma surgeons, and intensive care units.
There are several trauma scoring systems in use, but three of the most commonly used are ISS, RTS, and TRISS. Each serves a specific purpose and looks at different types of data:
The ISS focuses on the extent of injuries in six major body regions: head/neck, face, chest (thorax), abdomen/pelvis, limbs/pelvic girdle, and skin/soft tissues. Each region is assigned a severity score based on the most serious injury it has sustained. The top three scores are squared and added together to calculate the ISS. A higher score indicates more severe injuries, with a maximum score of 75. ISS is widely used to evaluate trauma severity in a consistent and objective manner.
RTS is a physiological scoring system that assesses how well the body is functioning after trauma. It uses three vital indicators: respiratory rate, systolic blood pressure, and Glasgow Coma Scale (GCS), which measures consciousness. Each factor is scored and weighted to give an overall RTS value. Lower RTS scores suggest more serious physiological compromise and greater urgency for intervention.
TRISS combines the anatomical information from ISS, the physiological data from RTS, and the patient’s age to predict the probability of survival. TRISS provides two different results—one for blunt (closed) injuries and another for penetrating injuries like stabbings or gunshots. It is especially valuable in trauma research and benchmarking trauma care performance across different hospitals and systems.
Together, ISS, RTS, and TRISS give healthcare providers a comprehensive understanding of a trauma patient's condition, from the injuries sustained to how the body is coping and what the outlook might be.
The Injury Severity Score (ISS) is a widely used medical scoring system that helps assess the seriousness of injuries sustained in different parts of the body. It was developed to provide a numerical value that reflects the overall trauma severity in a patient. The score is calculated based on the most severe injuries in up to three different body regions. The higher the score, the more severe the patient’s condition.
ISS is particularly helpful in emergency and trauma settings because it gives doctors and paramedics a quick snapshot of injury burden. It also plays a key role in deciding treatment plans, predicting outcomes, and comparing trauma care effectiveness across hospitals or trauma centers.
The ISS considers injuries in six main areas of the body. Each area is evaluated separately, and the most severe injury in each is scored using a system called the Abbreviated Injury Scale (AIS). The six regions are:
Each injury in the body is first rated on a scale from 1 to 6 using the Abbreviated Injury Scale (AIS). The ISS takes the three highest AIS scores (from different regions), squares each of them, and then adds them together. This gives the final ISS score, which ranges from 1 (minor injury) to 75 (unsurvivable injury).
The AIS severity levels are:
If any injury is scored as a 6 (maximum), the total ISS score is automatically set to 75, regardless of other injuries. This reflects the fact that such injuries are considered unsurvivable. In general, an ISS above 15 indicates major trauma, and patients with such scores usually require care at a specialized trauma center.
The Revised Trauma Score (RTS) is a physiological scoring system used to evaluate the immediate condition of trauma patients based on vital signs. Unlike anatomical scores such as the ISS, which focus on physical injuries, RTS looks at how the body is functioning in response to trauma. It is especially useful in pre-hospital and emergency room settings to quickly identify patients who are in critical condition and need urgent care or transfer to a trauma center.
The RTS is based on three key indicators of physiological health:
This measures how many breaths a person takes per minute. It reflects the patient's ability to breathe and oxygenate their body. Abnormal breathing rates can signal respiratory failure, shock, or brain injury.
This measures the pressure in the arteries when the heart beats. It helps assess whether the patient has adequate blood circulation. Low blood pressure can indicate internal bleeding or shock.
The GCS assesses a patient's level of consciousness by evaluating eye response, verbal response, and motor response. It is an important tool for detecting brain injuries.
Each of the three components (respiratory rate, systolic blood pressure, and GCS) is assigned a coded score from 0 to 4. These scores are then weighted and added using the following formula:
RTS = (GCS score × 0.9368) + (SBP score × 0.7326) + (RR score × 0.2908)
The final RTS value ranges from 0 (worst) to 7.8408 (best). A lower RTS indicates a more severe physiological disturbance and a higher risk of mortality. Medical staff use this number to quickly assess the severity of trauma and determine the urgency of care needed. It is particularly useful in triaging patients during emergencies or mass casualty incidents.
The Trauma Injury Severity Score (TRISS) is a composite scoring system used to estimate a trauma patient's probability of survival. It combines data from both anatomical and physiological assessments, making it one of the most comprehensive trauma scores in use. TRISS incorporates the Injury Severity Score (ISS), the Revised Trauma Score (RTS), and the patient’s age to predict the likelihood of surviving a traumatic injury.
TRISS is commonly used in emergency departments, trauma centers, and medical research to evaluate patient outcomes and compare the performance of different trauma care systems. It provides clinicians with a statistical estimate of survival chances, helping them make informed treatment decisions and assess whether further intervention is needed.
One of the unique features of TRISS is that it calculates survival probabilities differently depending on the type of trauma the patient has sustained. There are two main types:
TRISS uses different mathematical formulas to calculate survival probabilities for closed versus penetrating injuries, since the body responds differently to each type and outcomes vary.
Age is an important factor in trauma recovery, and TRISS takes this into account. The system distinguishes between two age groups:
This age adjustment helps ensure that survival estimates are more accurate and personalized, rather than applying the same prediction model to all patients.
TRISS uses a logistic regression formula that includes the patient’s RTS, ISS, and age to calculate the probability of survival. The formula differs slightly depending on the type of trauma:
Probability = 1 / (1 + e^(-b))b = -0.4499 + (0.8085 × RTS) - (0.0835 × ISS) - (1.7430 × AgeIndex)Probability = 1 / (1 + e^(-b))b = -2.5355 + (0.9934 × RTS) - (0.0651 × ISS) - (1.1360 × AgeIndex)In this formula, the AgeIndex is 1 if the patient is 55 years or older, and 0 if younger.
The result is expressed as a percentage (%), showing the patient's chance of survival. For example, a TRISS score of 85% means the patient has an estimated 85% probability of surviving their injuries. While TRISS is not perfect, it provides a valuable benchmark that combines injury severity, vital signs, and age in a single outcome prediction.
The Trauma Severity Scores Calculator is a user-friendly tool designed to help you quickly estimate the severity of a patient’s injuries and their chances of survival. It calculates three key scores: ISS (Injury Severity Score), RTS (Revised Trauma Score), and TRISS (Trauma and Injury Severity Score), all based on your input.
Start by selecting the level of injury for each of the six body regions listed in the calculator:
Each region has a drop-down menu where you can choose the severity of the injury—from "None" to "Maximum". The calculator automatically selects the three most severe injuries, squares their values, and adds them together to generate the ISS score.
Next, enter the physiological data required for the RTS calculation:
The calculator will assign scores to each input and use a weighted formula to determine the RTS score.
Finally, enter the patient’s age. TRISS calculations use age to adjust survival predictions:
The calculator then uses this along with ISS and RTS to estimate the patient’s probability of survival in both blunt (closed) and penetrating injury scenarios.
An ISS of 75 typically means the patient has a fatal injury, as this score reflects an AIS value of 6 in any region.
The lower the RTS, the more critical the patient’s condition.
The TRISS results will show the survival probabilities for two types of injuries:
These values are given as percentages. For example, a result of 92% means there is a 92% chance of survival based on the data entered. This helps healthcare providers assess risk and plan the level of care needed.
To better understand how the Trauma Severity Scores Calculator works, let’s walk through a few sample scenarios. These examples show how ISS, RTS, and TRISS are calculated and interpreted, and how they guide decisions in patient care.
ISS = 9² + 4² + 1² = 81 + 16 + 1 = 98 → But since we use only the three most severe scores, we take the top three ISS = 9² + 4² + 1² = 81 + 16 + 1 = 98. However, this exceeds the ISS maximum cap of 75, so ISS = 75.
RTS Inputs:
RTS = (4 × 0.9368) + (4 × 0.7326) + (4 × 0.2908) = 3.7472 + 2.9304 + 1.1632 = 7.84
Age: 35 (AgeIndex = 0)
TRISS (closed injury):
b = -0.4499 + (0.8085 × 7.84) - (0.0835 × 75) - (1.743 × 0)b = -0.4499 + 6.337 - 6.2625 = -0.3754TRISS = 1 / (1 + e^0.3754) ≈ 0.407 → 40.7%
ISS = 4² + 1² + 0² = 16 + 1 + 0 = 17
RTS Inputs:
RTS = (4 × 0.9368) + (4 × 0.7326) + (4 × 0.2908) = 7.84
Age: 25 (AgeIndex = 0)
TRISS (closed injury):
b = -0.4499 + (0.8085 × 7.84) - (0.0835 × 17)b = -0.4499 + 6.337 - 1.4195 = 4.4676TRISS = 1 / (1 + e^-4.4676) ≈ 0.988 → 98.8%
These examples show how trauma scores help medical teams understand injury severity and make fast, informed decisions:
Trauma severity scores help healthcare providers quickly assess how serious a patient's injuries are. They assist in making decisions about treatment, predicting survival chances, and prioritizing care in emergency situations.
These scores are commonly used by emergency room doctors, trauma surgeons, paramedics, and intensive care teams. They are also used in trauma research and hospital performance evaluation.
While the calculator is easy to use, trauma scores are designed for trained professionals. They interpret the results based on medical knowledge, patient condition, and clinical guidelines. If you're not a medical professional, use this tool for general understanding only—not for diagnosis or treatment.
A high ISS score indicates more severe trauma. Scores above 15 usually mean the patient has major injuries and may need specialized care in a trauma center. A score of 75 indicates an unsurvivable injury.
The maximum RTS score is 7.84, which indicates that the patient has normal vital signs and is physiologically stable. Lower scores indicate greater risk and instability.
TRISS provides two survival probabilities—one for closed (blunt) injuries and another for penetrating injuries. This distinction improves accuracy because the body responds differently to these types of trauma.
Yes. Older patients tend to have weaker physiological reserves and may take longer to recover from injuries. That’s why TRISS uses an age adjustment—patients aged 55 and older are statistically more at risk.
TRISS is generally used for adult trauma scoring. Although it can be used for older children, results may be less accurate for very young patients. Pediatric-specific tools are recommended for detailed assessment in children.
To get meaningful results, all required fields (injury locations, vital signs, and age) must be entered. Missing information will result in incomplete or inaccurate scores.
The scoring systems themselves (ISS, RTS, TRISS) have been in use for decades with minor updates. However, research is ongoing, and some hospitals may use modified versions or complementary tools based on the latest medical guidelines.
This Trauma Severity Scores Calculator is intended for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. The results generated by this tool are based on standardized scoring systems (ISS, RTS, and TRISS) and rely on user-provided data, which may not reflect the full clinical picture.
Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition or emergency. Never disregard professional medical advice or delay in seeking it because of something you have read or calculated using this tool.
Use of this calculator does not create a doctor-patient relationship. The developers and publishers of this tool are not responsible for any medical decisions, outcomes, or actions taken based on the information provided.