Food ‘Allergy’ Tests for Pets

Thankfully, food allergies in dogs and cats are uncommon. However, where they do occur, diagnosis and identification of the cause are difficult and time-consuming. With commercial testing services becoming more readily available, many owners are using these as a quick and simple way to find out what their pet is or may be, allergic to.
However, what many pet owners and even veterinarians may not realise is that common commercial blood- and saliva-based allergy tests have not been validated – i.e. there is no evidence to say that a positive result obtained by these tests correspond to any actual clinical signs of food allergy/food intolerance in pets. Equally a negative result does not necessarily mean that an ingredient/food is fine for a pet.
A scientific study1 published in 2019 found that saliva and blood tests for food allergies do not reliably distinguish between healthy dogs and those with food allergies. Over half (53%) of the healthy dogs showed weak positive reactions on the saliva test while 20-30% of the healthy dogs showed a strong positive reaction to certain food ingredients. Overall, there was no difference in the number of positive reactions to the tests between food-allergic and healthy dogs.
Another study performed with 30 healthy dogs (with no evidence of food allergies) found that between 60-100% of the dogs tested positive for one or more of the foods/ingredients in saliva and blood tests. This highlights how easy it is for a test result to come back positive!
Key messages:
• Saliva and blood tests for food allergies in dogs do not reliably distinguish between healthy and allergic dogs and should not be used for diagnosis of food allergy.
• Blood and saliva allergy tests could result in the false identification of lots of common pet food ingredients as allergens.
• This may push owners to avoid certain diets that include these ingredients when actually there is likely no need to avoid them.
• Where a pet has shown a genuine adverse reaction to food it has eaten, details of ingredients to be avoided need to be taken seriously and the owner should be advised to consult a Vet.
References
1. Udraite Vovk L, Watson A, Dodds WJ, et al. (2019) Testing for food-specific antibodies in saliva and blood of food allergic and healthy dogs. Veterinary Journal; 245: 1-6.
2. Lam ATH, Johnson LN & Heinze CR. (2019) Assessment of the clinical accuracy of serum and saliva assays for identification of adverse food reaction in dogs without clinical signs of disease. Journal of the American Veterinary Medical Association; 255: 812-816