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Frequently asked questions

The Feline Grimace Scale© (FGS) for veterinary professionals

Click here for the most up to date scientific information on the FGS.


Cat is sleeping

Do not disturb the cat and wait until he/she is awake for FGS scoring. Make sure the cat is truly sleeping (e.g. in a curled up position) and not showing signs of ‘feign sleep’ due to pain.


Cat is grooming, eating or playing

Wait until these activities are finished for FGS scoring.


Cat scored 4/10, but I am uncertain if it is indeed painful

Reassess the cat in 15-20 minutes.


I administered analgesics before surgery and when I scored the cat 45 minutes after surgery, the scores were 9/10.

FGS scores of 9/10 are high and the cat is probably painful requiring additional administration of analgesics. Analgesics are frequently required before, during and after surgery for optimal analgesia. See the ISFM Guidelines on Acute Pain Management.


Who can use the FGS?

Studies have shown that veterinarians, veterinary students and technicians/nurse, as well as cat carers can reliably use the FGS. 


Can I use the FGS for any type of acute pain?

Yes. The FGS was validated for use in cats with naturally-occurring acute medical and surgical pain including pain after dental extractions


What is the cut-off score for administration of rescue analgesia?

Rigorous statistical analysis from scientific studies studies with the FGS indicates that cats scoring ≥ 4/10 are likely to be in pain requiring the administration of rescue analgesia. 


Are there automated means to see if my cat is painful using the FGS? For example, can I take a picture of my cat and automatically know the if he/she is painful?

No. Some companies are advertising the use of the Feline Grimace Scale for automated assessment of cats’ emotions. However, the FGS was scientifically validated for evaluation of acute pain only and it should not be used for evaluation of other emotions (e.g. happiness or sadness). Our laboratory does not have any relationship with these companies and we are currently working on scientifically-sound methods to produce a robust, science-based tool with high specificity, sensibility and precision followed by peer-reviewed publications.


Cat is shy or fearful

Attempt to score the cat from a distance, if possible. Consider using fear-reducing and feline-friendly handling techniques for all patients to facilitate pain assessment. In our experience, shy or feral cats may present changes in facial expressions that may be due to anxiety and fear, and not always pain.  


Cat scored 3/10, but I think it could be painful

Reassess the cat in 15-20 minutes.


Cat scored 6/10 and I just administered an intramuscular injection of opioid

Reassess the cat in 30-40 minutes. The FGS scores should be reduced. If FGS scores have not decreased, a second dose of rescue analgesia might be required or a change in analgesic plan should be considered.


Can I assess pain in a patient by only looking at a photo?

Research  shows good agreement between real-time and image scoring. However, you must consider: 

1) The image must be representative of the cats’ facial expressions over several minutes. Changes in facial expression related to pain do not occur once in a split second. Changes in facial expressions are dynamic and may occur due to other things unrelated to pain (e.g. background noise, anxiety and fear).

2) The clinical context, cat’s history and physical examination must be evaluated along with the image. Cats with acute pain frequently show other changes in behavior associated with pain (e.g. decreased activity, decreased interest in the surroundings, decreased appetite, etc.).


I suspect this cat has osteoarthritis, should I use the FGS?

No. The FGS was developed for feline acute pain assessment. Other tools are available for assessment of osteoarthritis-related pain. See more information on chronic pain assessment in cats : 12, 3


Can I use the FGS to evaluate pain in other species?

No. The FGS was validated for use in cats only. Grimace scales for evaluation of pain in other nonhuman mammals are available.


Is there a phone application for the FGS?

Yes. You may freely download the FGS educational phone application in English, French or Spanish for Apple (App Store) and Android (Google Play) platforms. It allows the user to learn about the tool, practice his/her skills and helps with FGS scoring in real-time. 


I want to learn more about pain management in cats

Numerous resources about pain management in cats are freely available on this website and across the internet. For example, you can read the 2022 ISFM Guidelines on Acute Pain Management and 2022 WSAVA Global Pain Management Guidelines.   

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