Over the past few years more pet parents have been choosing raw food diets for their dogs and cats. More veterinarians are becoming raw feeding advocates, while others are not yet recommending them. Despite the increase in popularity of fresh and raw pet food, there are some in the veterinary community that continue to debate the effects of raw diets on laboratory blood and urine results. Blood testing results from pets that are raw fed will often differ from those of their kibble fed counterparts. This is something pet owners should be prepared for. The result is that some vets become alarmed when the raw fed pet’s blood values are skewed and may fall outside a “normal value” range. This can result in confusion, unnecessary concerns, additional tests, and follow-up care.
Dr. Jean Dodds and Dr. Susan Wynn conducted a study on raw-fed dogs. The goal of the two-part study was to (1) compare bloodwork results between kibble-fed and raw-fed dogs, and (2) evaluate the potential presence of increased protein in urine based on the results of part 1 of the study. The study included 227 raw-fed dogs and 75 healthy adult dogs who were fed a commercial kibble diet. The results of the study concluded that bloodwork results were essentially the same for raw and kibble-fed dogs, but with a few exceptions.
What are the exceptions in bloodwork and urine test results between kibble and raw-fed dogs and cats?
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Hematocrit – Hematocrit is the measurement of the percentage of red blood cells in
whole blood. This value is generally higher in raw fed dogs and cats. Raw fed pets are more likely to get adequate iron and vitamin B from their higher quality protein diets. Decreased Hematocrit (anemia) can be caused by poor nutrition, parasites or chronic disease including cancer and liver disease. Increased values are more of a concern for kibble-fed dogs and cats due to dehydration and a lack of moisture in the diet. - Blood urea nitrogen (BUN) – Urea is a waste product derived from protein breakdown in the liver. Urea leaves the liver through the blood, circulates, and ends up in the kidneys, where it passes through the body in the urine. BUN is typically higher in raw-fed dogs and cats because raw diets contain higher levels of protein. Since BUN is a marker for protein intake and kidney function, pets on raw diets often show slightly elevated BUN levels when compared to dogs eating a kibble-based diet.
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Creatinine - Creatinine reflects the body’s muscle mass. Creatine forms when food is
metabolized or changed into energy. Like Urea, it is a protein breakdown product.
Creatine breaks down to creatinine, which is passed from the blood to the kidneys and is disposed of through urine. Low levels are commonly seen with inadequate protein intake, liver disease, kidney damage or pregnancy. Slightly higher levels of creatinine are likely to be seen in raw-fed pets, who are eating biologically available proteins in higher percentages on a regular basis.
Drs. Dodds and Wynn concluded that the reference ranges for these bloodwork values should be revised for raw fed dogs. Their results are as follows:
| TEST RESULT | RAW FED DOGS | KIBBLE FED DOGS | NORMAL VALUES |
| Hematocrit | 51 ± 6.6 – 53.5 ± 5.6% | 47.6 ± 6.1% | 37 – 55% |
| BUN | 18.8 ± 6.9 – 22.0 ± 8.7mg/dL | 15.5 ± 4.7mg/dL | 6 – 24mg/dL |
| Creatinine | 1.20 ± 0.34mg/dL* | 1.07 ± 0.28mg/dL | 0.4 – 1.4mg/dL |
* Results found only in dogs fed a Volhard diet
As mentioned above, BUN and Creatinine tests are the primary tests used to check how well the kidneys can filter waste from the blood. In raw-fed dogs, this increase is not typically a cause for concern and may indicate strong muscle development and optimal protein utilization. However, a BUN-to-creatinine ratio above the reference range may be due to a condition called albuminuria, which is the presence of too much protein in the urine. The spillage could be due to a high dietary protein intake (raw diet) and/or increased leaking of protein through the glomerular kidney filtration system. Veterinarians who understand these values in raw-fed dogs will know the difference and recommend further testing if needed.
To provide additional clarity, the second part of Drs. Dodds and Wynn’s study focused on 37 healthy raw-fed dogs that tested positive for microalbuminuria. They concluded that a raw diet did not cause leakage of albumin into the urine of most (32) dogs tested, and that no short- or long-term clinical effects on renal function were detected. For the 5 dogs that tested positive for albuminuria, Dr. Dodds suggests a home-cooked diet for dogs with significant liver, kidney and bowel conditions. Light cooking helps break down the protein and other food ingredients, allowing for easier digestion.
What other clinical health markers differ between raw and kibble-fed dogs?
- Hydration and kidney health – Raw diets contain more moisture than kibble, resulting in better hydration levels. Proper hydration is essential for kidney health. Kibble-fed dogs rely more on water sources other than food to provide needed hydration.
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Blood glucose and insulin sensitivity – Raw diets contain a significantly lower level of
carbohydrates versus kibble diets. Many kibble formulas contain 30-60% carbohydrates, mostly from legumes and grains. Diets with high carbohydrates can lead to sugar spikes, which affect long-term health and insulin sensitivity. - Cholesterol and lipid profile – A raw diet’s natural, high quality fat content will exhibit healthy HDL (good cholesterol) and LDL (bad cholesterol) ratios. In contrast, dogs and cats fed kibble eat higher levels of processed fats and oils, which can influence lipid profiles. Kibble-fed pets may show elevated LDL cholesterol, which can indicate poorer cardiovascular health and contribute to a higher risk of obesity. This is more likely in lower-quality kibble that uses filler ingredients and artificial additives.
- Vitamin and Mineral Levels - Bloodwork in raw-fed dogs may show higher levels of vitamins B, C, and E and minerals like calcium and phosphorus, supporting better energy, bone health, and immune resilience. The synthetic vitamins and minerals found in kibble are less readily absorbed compared to natural sources from real food. This can result in lower or borderline levels of key nutrients in bloodwork, which may affect a kibble-fed dog’s energy levels, immunity, and bone health over time.
A study conducted in 2021 concluded that there are significant clinical differences between raw-fed and kibble-fed dogs and cats. Cats and dogs on a carefully planned, balanced raw diet receive high-quality, complete protein from animal sources that are more easily utilized than inferior protein sources in kibble. More pet parents are becoming educated in understanding the value in feeding raw and minimally processed food. Understanding bloodwork differences between raw-fed and kibble-fed dogs offers pet owners a clearer picture of how diet affects their pet’s health at a cellular level. By recognizing the impact of diet on hydration, protein utilization, blood sugar
stability, and immune function, owners can make more informed decisions and monitor their pet’s health more effectively. Vets with an understanding of raw feeding know what values to look for in the blood. Be sure to let your veterinarian know what you are feeding your dog or cat. Feeding a species-appropriate raw or gently-cooked diet will go a long way in contributing to optimal health for your pet.
Disclaimer: This content is for informational purposes only and is not meant to diagnose, treat, or replace consulting a primary veterinarian for individualized care.