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Dog food allergy tests: Do they work and are they worth it?

Vet talking through the result of dog food allergy tests on a Pug with owner
(Image credit: Getty Images)

If you read any dog magazines or participate in any dog owners’ social media groups, you have probably seen information about a number of new dog food allergy tests. Conventionally, allergy testing was performed only by a veterinarian. Now, however, there are an increasing number of companies claiming to offer home allergy tests that can diagnose your dog’s allergies with just a small fur or saliva sample. 

Despite these apparent new advances, the ideal method of diagnosing canine food allergies continues to be the food trial. Intradermal testing and blood allergy tests (performed by a veterinarian) can be beneficial in the case of other allergies, but are typically not helpful in the case of food allergies. At-home allergy tests are largely regarded as unreliable. If you are feeding your pup the best dog food for allergies and your dog continues to have skin issues, a conversation with your veterinarian can help you determine the next steps for your dog. 

Can you test dog allergies at home?

In recent years, several “at home” allergy testing kits have been developed and marketed for dogs. These tests claim to be able to diagnose your dog’s allergies using a small sample of your dog’s fur or saliva, which is then sent to a laboratory for analysis.

While this sort of testing may sound convenient and appealing, the results of these tests should be regarded as suspect. In fact, one company failed to recognize fake hair and fake saliva when submitted by researchers, which makes veterinarians question the testing that is really taking place on the samples submitted by clients. Given the numerous questions about the validity of these at-home tests, you are probably better off investing your money in appropriate veterinarian-recommended allergy testing. 

Intradermal and blood allergy testing: Are these dog food allergy tests accurate?

Dogs can develop allergies to a variety of substances. For more information, read our guide about the four common allergies in dogs. Allergy tests that are performed by veterinarians or veterinary dermatologists can be highly effective in diagnosing environmental allergies, but are typically less appropriate for food allergies.

There are two types of veterinary allergy tests: intradermal skin testing and blood allergy tests. In intradermal skin testing, your dog is injected with small amounts of potential allergens (while sedated or anesthetized) and a veterinary dermatologist monitors your dog’s skin reactions to these injections. In blood allergy testing, a sample of your dog’s blood is collected and tested for reactivity against various allergens. Both of these tests are very helpful in diagnosing a dog with atopy (allergies to inhaled, environmental allergies), but neither should be used to diagnose food allergies. 

How do they test for food allergies in dogs?

Dog scratching outside

(Image credit: Getty Images)

The most accurate test for food allergies is a “food trial.” This requires feeding your dog a highly restricted diet for a period of eight to twelve weeks, to see if your dog’s allergy signs improve. If your dog’s signs improve on a hypoallergenic diet, then return when allergens are reintroduced, you can conclude that your dog has food allergies. 

Dogs can be allergic to nearly any protein in their food. Three common food allergies in pets include beef, dairy, and chicken allergies; however, dogs can be allergic to any plant or animal protein to which they have had previous exposure. Therefore, a food trial requires feeding a diet that doesn’t contain any proteins that could potentially trigger an allergic reaction. 

Food trials are typically performed using a hydrolyzed protein diet. The proteins in these diets are broken down into fragments that are too small to trigger an immune reaction. The most common diets used in food trials are Hills Prescription Diet z/d Skin/Food Sensitivities Dog Food and Royal Canin Hydrolyzed Protein HP Dog Food. These diets can be purchased at veterinary clinics, pet stores, or online, but both will require a prescription from your veterinarian.

When performing a food trial, it isn’t only your dog’s regular diet that needs to be changed. You also need to be sure your dog doesn’t eat anything else that could trigger a reaction. Talk to your veterinarian about hypoallergenic treats and unflavored parasite prevention, and devise a way to keep your dog out of the trash during the food trial. While a food trial can be challenging, it is the best way to determine whether your dog has food allergies. 

How much does a dog food allergy test cost?

Hydrolyzed protein diets are relatively expensive. Not only do they require special manufacturing processes, they also must be produced on a dedicated manufacturing line to prevent contamination from other foods. 

In general, you can expect to pay roughly $50-100 for a bag of hypoallergenic dog food. The cost of a food trial will depend on the size of your dog and the duration of your food trial. If you have a small dog and improvement occurs within a few weeks, a food trial may cost you as little as $50 (the cost of a single small bag of hypoallergenic food). On the other hand, if your large breed dog requires a 12-week food trial, you may spend several hundred dollars on hypoallergenic food. 

If your dog is diagnosed with food allergies, they will likely remain on a restricted diet for the rest of their lives. Fortunately, feeding costs will likely go down. While some owners choose to continue a hydrolyzed diet long-term, most owners are able to find a more affordable option for long-term feeding. 

Summary

While you may hear about dog food allergy tests that can be performed on your pet’s blood, fur, or even saliva, it’s important to realize that these tests are often inaccurate. If you suspect your dog may have a food allergy, talk to your veterinarian about a food trial. Feeding a hypoallergenic diet for just eight to twelve weeks can allow a definitive diagnosis, paving the way for effective treatment. 

Catherine Barnette DVM

Dr. Barnette is a graduate of the University of Florida, where she received both her B.S. in Zoology and her Doctor of Veterinary Medicine (DVM). She has 15 years of clinical experience as a small animal veterinarian, treating dogs, cats, and occasional exotic patients. She now works as a freelance veterinary writer, creating educational content for veterinarians, veterinary team members, and dedicated pet owners. Dr. Barnette lives in southwest Florida with her husband and daughter (plus two cats, a dog, and a rescued dove!) and enjoys kayaking, biking, and hiking. Learn more about Dr. Barnette at www.linkedin.com/in/catherinebarnette.