# Canine Pain Scales: Glasgow CMPS-SF and Colorado State Explained ## Key Takeaways - The Glasgow Composite Measure Pain Scale short form (CMPS-SF) scores six behavior categories in dogs for a maximum of 24 points, or 20 points when mobility cannot be assessed. - The CMPS-SF developers set the analgesic intervention threshold at 6 of 24 points, or 5 of 20 points when the mobility category is excluded. - The Colorado State University acute pain scale is a 0 to 4 instrument that is faster to use than the Glasgow CMPS-SF but has not been formally validated. - The CMPS-SF should be performed in a fixed sequence: observe the dog from a distance, approach and interact, palpate near the wound, then score and act. - In trained evaluators the CMPS-SF showed intra-observer reliability of 0.80 to 0.99 and inter-observer reliability of 0.73 to 0.86, but agreement among mixed hospital teams was poor. ## The Direct Answer Dogs cannot report pain in words, so veterinarians use structured behavior-based scoring systems to convert what a dog does into a number that drives treatment. The Glasgow Composite Measure Pain Scale short form (CMPS-SF) is one of the most widely used and best-validated acute pain scales in dogs. It scores six behavior categories for a maximum of 24 points, or 20 points when mobility cannot be assessed, and the developers set the intervention threshold at 6 of 24 or 5 of 20 [1]. The Colorado State University acute pain scale is a simpler 0 to 4 instrument that many general practices use because it is fast, but it has not been formally validated the way the Glasgow tool has. For owners watching a dog recover from surgery: a dog that is restless, tense, guarding the incision, unwilling to look at or be touched near the wound, or unusually quiet and withdrawn may be in pain even without whining. Pain in dogs is a behavior change, not a volume level. If your dog was sent home after surgery and the behavior you are seeing does not match the discharge instructions, call the clinic. Do not wait for the next scheduled recheck. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Why Pain Scoring Exists Pain is a protective mechanism. It involves sensing tissue damage and experiencing the associated discomfort, aversion, and negative emotions, and those aspects are multidimensional and subjective [3]. That subjectivity is the central problem in veterinary medicine. There is no gold standard for measuring pain in dogs, and no blood test or monitor that reads it directly [3]. Older approaches leaned on physiologic numbers such as heart rate, blood pressure, and pupil size. Those variables are not specific for pain and vary widely between individual dogs, so they cannot stand alone as a pain measure [3]. Behavior, scored in a structured and repeatable way, became the practical foundation. The Glasgow scale was built from that foundation. Investigators collected 279 words and expressions suggested by 69 veterinary surgeons and reduced them to 47 descriptors allocated into seven behavior categories: demeanor and response to people, posture, mobility, activity, response to touch, attention to painful area, and vocalization [4]. Three statistical methods (hierarchical agglomerative cluster analysis, Cronbach's alpha, and analysis of variance with multiple comparisons and empirical cumulative distributions) were used to validate the structure, and a questionnaire with a list of definitions was designed around the retained expressions [4]. The short form that clinicians use today is a multi-item behavioral tool developed and validated with a psychometric approach to measure acute pain in dogs [1]. That origin story matters clinically. The CMPS-SF is not a checklist someone invented at a conference. It is a psychometrically constructed instrument, and the way it is used (the observation sequence, the scoring rules, the intervention threshold) is part of what makes it valid. ## The Glasgow CMPS-SF: Structure and Scoring ### The Six Behavior Categories The CMPS-SF asks the assessor to score six behavioral domains. Each domain contains several descriptors, and the assessor selects the single descriptor that best matches the dog. The descriptors carry different point values, so not every category contributes equally to the total. The categories are: 1. **Vocalization.** From quiet through crying or whimpering, groaning, and screaming. 2. **Attention to wound or painful area.** Whether the dog looks at, licks, chews, or rubs the painful area. 3. **Demeanor.** The dog's overall demeanor, ranging from happy and content through quiet, indifferent, and nervous or fearful to depressed or non-responsive to stimulation. 4. **Posture.** Whether the dog stands or lies in a normal, comfortable position or adopts a stiff, hunched, or abnormal posture. 5. **Mobility.** Willingness and ability to move, including rising and walking. 6. **Response to touch.** How the dog reacts when the painful area is approached and palpated. The maximum total is 24 points. When mobility cannot be assessed, for example because the dog will not or cannot walk, that category is excluded and the maximum becomes 20 points [1][2]. ### The Intervention Threshold The developers set the analgesic intervention level at **6 of 24**, or **5 of 20** when mobility is excluded [1]. A dog scoring at or above that level should receive additional analgesia. A later validation of the Portuguese version, using the COSMIN and GRADE frameworks, proposed a slightly lower cut-off point for rescue analgesia of 5 or higher, or 4 or higher when the mobility item is excluded, with specificity of 78 to 87 percent and sensitivity of 74 to 83 percent [2]. That is a later proposal from one validation study, not a change to the original threshold. In day-to-day practice, the developer-stated threshold of 6 of 24 (or 5 of 20) is the number most clinicians are trained on, and it is the number to use unless your hospital has adopted a different validated cut-off. ### Why the Threshold Number Matters A pain score without an action rule is just documentation. The intervention threshold is what converts the score into a decision. This is also why the scoping review of 114 studies using the CMPS-SF flagged modifications to the scale and to the intervention level as a problem: changes to either can alter the validity of the instrument [1]. If a practice shortens the form, changes the descriptor wording, or moves the treatment threshold, it is no longer using a validated tool in a validated way. ## How to Perform the Glasgow CMPS-SF The scale is meant to be performed in a fixed sequence. The sequence is not a formality. Each step reveals different behaviors, and skipping steps produces scores that do not mean what the number implies. ### Step 1: Observe From a Distance Watch the dog before interacting. Stand outside the kennel or at the edge of the exam area, listen for vocalization, and look at posture, activity level, and whether the dog is attending to the wound. A dog that is comfortable will typically rest in a normal position. A dog in pain may be rigid, hunched, or unwilling to settle. This step captures the posture and activity information that disappears the moment you open the door. ### Step 2: Approach and Interact Open the kennel or approach the dog and assess demeanor and response to people. Note whether the dog is content, interested, anxious, fearful, or aggressive. Some dogs become unusually quiet when painful rather than noisy, so an absence of whining is not evidence of comfort. Then, unless the dog cannot or should not walk (for example with spinal, pelvic, or multiple limb fractures), put a lead on the dog and walk it out of the kennel to score mobility. ### Step 3: Palpate Near the Wound Apply gentle pressure to the area about 2 inches (5 cm) around the surgical site or painful area, and score the response to touch. This is the step that most directly probes the source of pain. A dog that turns, tenses, whines, or tries to bite when the area is approached is telling you something specific. The order matters because a dog that has just been palpated is aroused, and arousal contaminates the observation of resting posture and demeanor. Observe first, interact second, palpate last. ### Step 4: Score and Act Select the single best descriptor in each category, total the points, and compare the total to the threshold. Record the score, the time, and the intervention. Repeat scoring at defined intervals so that the trend, not just the single number, guides care. ### Practical Points That Change Scores - **Score the dog, not the surgery.** Two dogs with identical procedures can score very differently. - **Use the definitions.** The original instrument was designed around a questionnaire with a list of definitions, and the descriptors are not self-explanatory to a first-time user [4]. - **Do not score a dog that is still heavily sedated.** Sedation suppresses or distorts the behaviors the scale depends on. Wait until the dog is sufficiently recovered to show normal behavior. - **Score before and after analgesia.** A falling score after treatment is evidence the treatment worked. A flat or rising score means the plan needs to change. ## Reliability: What the Evidence Actually Shows The CMPS-SF has been translated and validated in multiple languages, and those studies confirm its core psychometric properties. The Italian version demonstrated construct validity in 95 dogs undergoing orthopedic or soft tissue surgery, with significant differences in median pain scores between orthopedic and soft tissue cases and among mild, moderate, and severe cases, and median scores decreasing over time [5]. The European Portuguese version showed the same pattern in 68 dogs, with significant differences between soft tissue and orthopedic cases and between mild and moderate cases, and median scores falling with time [6]. A more demanding validation of the Portuguese version assessed 208 videos of 52 dogs with four trained evaluators. The CMPS-SF behaved as a unidimensional scale. Intra-observer reliability was 0.80 to 0.99 and inter-observer reliability was 0.73 to 0.86. Criterion validity was confirmed by correlation with other unidimensional scales at 0.7 or higher. Internal consistency was 0.7 by Cronbach's alpha and 0.77 by McDonald's omega [2]. Those are strong numbers for a behavioral instrument. The reliability picture changes when you look at real-world users rather than trained evaluators. A study comparing veterinary students, veterinary nurses, veterinary surgeons without specific anesthesia training, and European College of Veterinary Anaesthesia and Analgesia diplomates found good to excellent agreement between groups, but overall agreement among all assessors was poor and intra-group agreement was poor to moderate [7]. Veterinary students tended to score pain higher than more experienced assessors [7]. In other words, the scale is reliable in trained hands and noisier in a mixed-team hospital, and less experienced assessors lean toward over-treating rather than under-treating. The scale also responds to non-pain factors in predictable ways. A study of bitches undergoing ovariohysterectomy found that a 45-minute positive dog-owner interaction after surgery significantly decreased post-operative pain perception and stress scores measured with the CMPS-SF, with the descriptors for nervous, anxious, or fearful decreasing and happy, content, or bouncy increasing in the group that received the visit [8]. That is a useful reminder that the score reflects the dog's emotional state as well as its nociception, and that owner presence is itself an intervention. ## The Colorado State University Acute Pain Scale ### What It Is The Colorado State University acute pain scale is a 0 to 4 instrument built around observation and palpation. The assessor observes the dog's behavior and then palpates the affected area, and assigns a single score from 0 (no pain) to 4 (severe pain). It is faster than the Glasgow tool because it produces one number rather than six category scores. ### How It Differs From the Glasgow CMPS-SF The critical difference is validation. The Glasgow CMPS-SF was developed and validated with a psychometric approach [1], and its performance has been confirmed across languages and observer groups [5][6][2]. The Colorado State scale is widely used and clinically useful, but it has not been formally validated in the same way. That does not make it wrong. It means the numbers it produces have less evidence behind them, and the threshold for treatment is a clinical judgment rather than a published cut-off. ### When the Colorado State Scale Makes Sense A simple 0 to 4 scale is practical in a busy general practice where a technician needs a quick, repeatable read on a recovering patient. It is also easier to teach to a new team member than a six-category instrument with weighted descriptors. The trade-off is precision. If your practice uses the Colorado State scale, use it consistently, document trends, and recognize that the Glasgow CMPS-SF remains the reference standard when a validated number is needed, for example in a research setting or when a patient's pain is difficult to control. ## At a Glance: Comparing the Scales | Feature | Glasgow CMPS-SF | Colorado State University Acute Pain Scale | |--|--|--| | Structure | Six behavior categories with weighted descriptors | Single 0 to 4 rating | | Maximum score | 24, or 20 when mobility cannot be assessed | 4 | | Intervention threshold | 6 of 24, or 5 of 20 | Clinical judgment, no published cut-off | | Method | Observe in the kennel, walk on a lead, apply gentle pressure near the wound, then score overall demeanor and posture | Observe, then palpate | | Formal validation | Yes, psychometric development and multi-language validation | Not formally validated | | Best use | Acute post-operative and acute medical pain, research, difficult cases | Rapid bedside screening in general practice | | Reported reliability | Intra-observer 0.80 to 0.99, inter-observer 0.73 to 0.86 in trained evaluators [2] | Not established in the same way | | Main limitation | Requires training and a fixed observation sequence | Less precise, no validated treatment threshold | ## Chronic Pain Tools: A Different Problem Acute pain after surgery is a short, observable event. Chronic pain, most commonly from osteoarthritis, is a long, slow, home-based problem, and the tools are different because the observer is different. The owner sees the dog every day. The veterinarian sees the dog for twenty minutes. ### Canine Brief Pain Inventory The Canine Brief Pain Inventory (CBPI) is an owner-administered questionnaire that assesses chronic pain in terms of severity and interference with daily life activities [9]. It was adapted from a human measure, the Brief Pain Inventory, to capture owner-perceived pain and the impact of that pain on the dog's daily functioning [10]. Factor analysis consistently confirms a two-factor structure: a pain severity score and a pain interference score [9][11]. In the Italian validation, pain severity and interference items showed mean inter-item correlations of 0.90 and 0.80 respectively, with communality ranging from 0.84 to 0.97, and Cronbach's alpha of 0.97 for pain severity and 0.96 for pain interference [9]. The French validation found mean inter-item correlations of 0.74 and 0.53, with Cronbach's alpha of 0.91 and 0.87, and a strong negative correlation between both scores and overall quality of life [11]. The CBPI has been translated and linguistically validated for global use across Australia, China, Germany, Hungary, Ireland, Japan, the Netherlands, and Portugal, with cognitive debriefing confirming that the translations convey the original concepts and that owners find the items easy to understand [10]. A Spanish translation has also been produced and linguistically validated [12]. The instrument is practical for tracking response to treatment over months. In one report, a working police dog with severe elbow osteoarthritis was tracked with the CBPI before treatment and at intervals up to six months, with pain scores declining until the three-month evaluation and rising toward baseline by six months [13]. ### Helsinki Chronic Pain Index The Helsinki Chronic Pain Index is another owner-completed instrument for chronic pain in dogs. It is referenced in the broader pain assessment literature as one of the established scales used to evaluate chronic pain and guide analgesic and medical treatment [3]. Like the CBPI, it depends on owner observation over time rather than a single clinic visit. ### WSAVA Pain Guidelines The World Small Animal Veterinary Association publishes global guidelines that address pain assessment and management in small animal practice. These guidelines frame pain scoring as part of routine care rather than an optional extra, and they support the use of validated instruments where they exist. The practical takeaway for a general practice is that pain should be assessed with a consistent tool at consistent intervals, and the tool should match the problem: an acute validated scale for post-operative and acute pain, and an owner-completed chronic instrument for osteoarthritis and other long-term conditions. ## Limitations That Change the Score ### Sedation Sedation is the most common reason a pain score is wrong. A sedated dog cannot show normal posture, mobility, or response to people, and the behaviors the scale depends on are suppressed. Scoring a dog that is still emerging from anesthesia produces a number that reflects drug effect, not comfort. Wait until the dog is sufficiently recovered to behave normally, then score. ### Anxiety, Fear, and Stress Anxiety and fear produce behaviors that overlap with pain behaviors. A frightened dog may be tense, may resist handling, and may vocalize, all of which raise the score. The dog-owner interaction study demonstrated the reverse effect: a positive interaction lowered pain and stress scores and shifted descriptors toward happy and content [8]. The scale measures the dog's emotional state along with its nociception, which is a feature for welfare but a complication for interpretation. ### Breed and Temperament Breed and individual temperament shape how a dog expresses pain. Some dogs are stoic and show almost nothing until pain is severe. Others are dramatic about minor discomfort. The literature on pain assessment notes that species- and animal-specific factors including age, breed, clinical condition, and anxiety need to be considered, and that physiologic parameters vary widely between individuals [3]. A single score taken in isolation, without knowledge of the dog's normal behavior, is weaker than a score interpreted against a baseline. ### Observer Training and Experience The scale is only as good as the person using it. In the multi-observer study, overall agreement among all assessors was poor and intra-group agreement was poor to moderate, with students scoring higher than experienced assessors [7]. This means two people can look at the same dog and reach different numbers. The fix is training, a fixed observation sequence, and consistency: the same person scoring the same dog over time produces a more useful trend than different people producing scattered numbers. ### The Absence of a Gold Standard There is no gold standard for pain assessment in dogs [3]. Every scale is a proxy. The CMPS-SF is the best-validated proxy for acute pain, and the CBPI is well validated for owner-reported chronic pain, but neither reads pain directly. A score supports a clinical decision. It does not replace clinical judgment. ## Pain Scoring in Context: What It Is For Pain scoring is not an academic exercise. Its purpose is to make sure dogs receive adequate analgesia and to make sure they are not over-treated. The scoping review of 114 studies using the CMPS-SF found widespread use of the scale and also found that many studies had deficiencies in reporting experimental design, including the observers used, the underlying hypothesis, the primary outcome, and a priori sample size calculations, which may predispose to statistical errors in the small animal pain literature [1]. The same discipline that improves research improves practice: define who is scoring, when they are scoring, and what action follows a given score. For a general practice, a workable protocol is straightforward. Score every surgical patient with the CMPS-SF at fixed intervals after extubation. Treat at the validated threshold. Re-score after treatment. Use the Colorado State scale for rapid screening when a full CMPS-SF is not practical, and recognize its limits. For chronic cases, send the owner home with a validated owner-completed instrument such as the CBPI and review the trend at rechecks. ## Limitations and When to Contact a Veterinarian No pain scale replaces a veterinarian's assessment of an individual dog. A score is one input among history, physical examination, and the dog's response to treatment. Contact a veterinarian promptly if a dog recovering from surgery or injury shows any of the following: - Restlessness, pacing, or an inability to settle that persists or worsens - Tense, hunched, or rigid posture that does not relax - Guarding, licking, chewing, or rubbing at the surgical site - Crying, whining, or vocalizing that is new or increasing - Reluctance or refusal to move, rise, or walk - Flinching, tensing, or attempting to bite when the painful area is approached - Unusual quietness, withdrawal, or unresponsiveness in a dog that is normally interactive - A pain score at or above the intervention threshold that does not improve after the prescribed analgesia Escalation is warranted when the dog's behavior does not match the expected recovery timeline, when the prescribed analgesia does not appear to be working, or when the dog's condition changes in any way that concerns you. A phone call is cheap. Untreated post-surgical pain is not. ## Frequently Asked Questions ### What is the Glasgow Composite Measure Pain Scale short form? It is a validated, behavior-based acute pain scale for dogs with six categories and a maximum score of 24, or 20 when mobility cannot be assessed. ### What score on the Glasgow pain scale means a dog needs more pain relief? The developers set the intervention threshold at 6 of 24, or 5 of 20 when mobility is excluded. ### How do you perform the Glasgow CMPS-SF? Observe the dog in the kennel for vocalization and attention to the wound, walk it on a lead to assess mobility, apply gentle pressure around the wound to score response to touch, then score overall demeanor and posture. ### Is the Colorado State pain scale the same as the Glasgow scale? No. The Colorado State scale is a 0 to 4 observation and palpation tool that has not been formally validated, while the Glasgow CMPS-SF is a validated six-category instrument. ### Why is my dog's pain score different depending on who checks it? Pain scoring depends on observer training and experience, and studies show poorer agreement between different assessors than within a single trained assessor over time. ### Can sedation affect a dog's pain score? Yes. Sedation suppresses the behaviors the scale relies on, so a dog should be sufficiently recovered before scoring. ### What tools are used for chronic pain in dogs? Owner-completed questionnaires such as the Canine Brief Pain Inventory and the Helsinki Chronic Pain Index are used for chronic pain such as osteoarthritis. ### Does a low pain score mean my dog is comfortable? Not necessarily. Some dogs are stoic and hide pain, so a low score should be interpreted alongside the dog's normal behavior and the clinical picture. ## Related Articles - [Can You Give Your Dog Tylenol? The Danger Explained](/knowledge/veterinary-medicine/pet-medication-guide/dog-tylenol-danger) - [How to Use a Quality of Life Scale for Your Senior Dog: A Practical Guide](/knowledge/veterinary-medicine/senior-and-chronic-care/quality-of-life-scale-senior-dog) - [Can You Give Your Dog Tramadol for Pain?](/knowledge/veterinary-medicine/pet-medication-guide/can-you-give-dog-tramadol-pain) - [Feline Grimace Scale: How to Score Pain in Cats](/knowledge/veterinary-medicine/anesthesia-analgesia/feline-grimace-scale) - [Caring for a Dog After Surgery: Pain Management Rest and Wound Monitoring](/knowledge/veterinary-medicine/life-stage-emergency-care/caring-for-a-dog-after-surgery-pain-management-rest-and-wound-monitoring) - [How to Tell If Your Dog's Pain Medication Is Working](/knowledge/veterinary-medicine/pet-medication-guide/dog-pain-medication-effectiveness) ## Sources 1. [The Short Form of the Glasgow Composite Measure Pain Scale in Post-operative Analgesia Studies in Dogs: A Scoping Review.](https://pubmed.ncbi.nlm.nih.gov/34660773/) 2. [Validation of the Portuguese Version of the Short-Form Glasgow Composite Measure Pain Scale (CMPS-SF) According to COSMIN and GRADE Guidelines.](https://pubmed.ncbi.nlm.nih.gov/38539929/) 3. [Assessment of acute and chronic pain in canine internal medicine: what is missing in our diagnostic toolbox?](https://www.semanticscholar.org/paper/b3993c4d059e13acf51d23587b0787c41681f043) 4. [Development of a behaviour-based scale to measure acute pain in dogs.](https://pubmed.ncbi.nlm.nih.gov/11354645/) 5. [CREATION AND VALIDATION OF THE ITALIAN VERSION OF THE GLASGOW COMPOSITE MEASURE PAIN SCALE-SHORT FORM (ICMPS-SF).](https://pubmed.ncbi.nlm.nih.gov/30575003/) 6. [Creation of the European Portuguese version of the Glasgow Composite Measure Pain Scale - short form (CMPS-SF) and initial psychometric evaluation.](https://pubmed.ncbi.nlm.nih.gov/41131599/) 7. [Agreement of Pain Assessment Using the Short Form of the Canine Glasgow Composite Measure Pain Scale between Veterinary Students, Veterinary Nurses, Veterinary Surgeons, and ECVAA-Diplomates](https://www.semanticscholar.org/paper/2dec7d8861f98015e234ce161dcb66d79d049acc) 8. [Effect of dog-owner interaction on post-operative pain perception and stress of dogs and variability in their behavioural patterns.](https://pubmed.ncbi.nlm.nih.gov/39600353/) 9. [Initial Psychometric Testing and Validation of the Italian Version of the Canine Brief Pain Inventory in Dogs With Pain Related to Osteoarthritis.](https://pubmed.ncbi.nlm.nih.gov/34604372/) 10. [Linguistic Validation of the Canine Brief Pain Inventory (CBPI) for Global Use.](https://pubmed.ncbi.nlm.nih.gov/34912877/) 11. [Initial psychometric testing and validation of the French version of the Canine Brief Pain Inventory.](https://pubmed.ncbi.nlm.nih.gov/31301964/) 12. [Translation to Spanish and linguistic validation of the Canine Brief Pain Inventory.](https://pubmed.ncbi.nlm.nih.gov/37456964/) 13. [Evaluation of the Effect of Mesotherapy in the Management of Osteoarthritis-Related Pain in a Police Working Dog Using the Canine Brief Pain Inventory.](https://pubmed.ncbi.nlm.nih.gov/28750790/)