What Changes in Your Dog's Blood Work on a Natural Diet, and How to Read It With Your Vet
If your dog eats fresh, air-dried, or minimally processed food, some blood markers will look different from the printed "normal" range. This isn't cause for alarm. It's something worth understanding, so you and your vet can interpret results together.
This article doesn't argue that blood tests are unreliable, or that vets are interpreting things incorrectly. It does something more useful: it explains what genuinely changes in blood chemistry when a dog eats high-quality natural food, so that you can walk into your vet's clinic with better context — and have a more informed conversation.
The goal is a pet parent and vet on the same page. Not one correcting the other.
Why Your Dog's "Normal" May Not Be on That Lab Sheet
When a blood test comes back and certain values are flagged, the comparison point is always a reference range - the band of values that represents "typical healthy dogs." This range was established over decades of veterinary research.
Here's the context that's worth knowing: most of that research was conducted on dogs eating commercial dry kibble, because that's what the vast majority of dogs eat. That's not a flaw in the research. It's just what the data reflects.
Dry kibble is typically around 10% moisture, 30–60% carbohydrates, and uses mixed animal and plant protein sources processed at very high temperatures. A dog whose entire life has been spent eating that diet has a particular metabolic baseline - and that baseline became the reference standard.
Your dog on a fresh, air-dried, or raw diet is eating something genuinely different: higher animal protein, more moisture from food itself, fewer processed carbohydrates, and lower inflammatory load from additives and heat-damaged fats. Their body reflects that difference - including in blood chemistry.
Veterinary researchers Dr. Jean Dodds and Dr. Susan Wynn studied over 200 dogs across kibble-fed and naturally-fed groups and reached a clear conclusion: reference ranges for naturally-fed dogs need to be considered separately from those built on processed diets. [1] This isn't fringe opinion — it's a documented research finding that informs how progressive clinicians approach nutrition-aware blood panel reading.
What Actually Changes — and Why
Most blood values stay entirely consistent regardless of diet. The differences that show up in naturally-fed dogs are specific and predictable. Here's what to look out for, what drives each shift, and how a vet familiar with natural diets will read it.
How to read it: BUN on its own doesn't tell you much. A vet will look at BUN and creatinine together, alongside hydration status and whether the dog has any symptoms. An elevated BUN with a normal creatinine in a healthy, hydrated dog is almost always dietary.
Why this matters: This is exactly what makes creatinine the more reliable kidney marker for naturally-fed dogs. BUN rises because of diet, Creatinine doesn't. So if creatinine is significantly elevated alongside BUN, diet is no longer a sufficient explanation. That combination is what warrants investigation, not BUN alone.
How to read it: A mildly elevated ALT alongside normal ALP and normal bilirubin in an active, symptom-free dog is very rarely cause for immediate intervention. The right follow-up is bile acid testing, not alarm.
Important exception: A significant drop in platelets accompanied by fever, lethargy, or tick exposure history should always be investigated for tick-borne disease (Ehrlichiosis, Anaplasmosis). That's a separate matter from diet entirely.
| Marker | Typical on Kibble | On Natural Diet | What It Reflects |
|---|---|---|---|
| BUN | Moderate | Higher | More protein metabolism — dietary, not renal |
| Creatinine | Normal range | Largely stable | Not diet-driven — the reliable kidney signal |
| Haematocrit | Moderate | Higher | Better iron & B-vitamin absorption |
| ALT | Can be elevated | Mildly elevated possible | Read alongside ALP + Bilirubin, not alone |
| Platelets | Moderate | Slightly lower possible | Lower inflammatory baseline |
| Total Protein | Lower | Higher | Better amino acid availability |
| Glucose | Higher | Lower, stable | Fewer carbohydrates — metabolic advantage |
How to Look at a Panel — Clusters, Not Single Numbers
The most important shift in how you read your dog's blood work is moving from single-number thinking to pattern thinking. Real clinical concern almost always shows up across multiple markers simultaneously, and alongside physical symptoms.
Here are the clusters worth understanding:
For kidney health — look at all four together
BUN + Creatinine + SDMA + Urine Specific Gravity. The key distinction here is this: BUN rises on a high-protein diet. Creatinine largely doesn't — it's cleared by the kidneys through glomerular filtration and isn't meaningfully influenced by what the dog is eating. So on a natural diet, you'd expect BUN to be elevated while creatinine stays relatively stable. That's a dietary pattern. If creatinine is also climbing significantly alongside BUN, that combination can no longer be explained by diet — the kidneys aren't clearing it properly, which is a different matter entirely. SDMA is a newer, more sensitive marker that detects kidney dysfunction at 40% function loss — versus 75% for BUN alone — and is also unaffected by protein intake. [6] It's worth requesting specifically if kidney health is a concern.
For liver health — look at the full enzyme panel
ALT + ALP + Bilirubin together. A mildly elevated ALT with normal ALP and bilirubin in an active dog is not the same picture as ALT and ALP both rising significantly alongside lethargy or jaundice. If there's any genuine concern, bile acid testing (pre- and post-prandial) is the appropriate next step. [7]
And always factor in the dog in front of you
Energy. Appetite. Coat quality. Stool consistency. Muscle condition. These are the upstream signals. Blood values and physical presentation together tell a complete story. A number in isolation rarely does.
- BUN elevated, creatinine normal or slightly elevated, SDMA normal
- Haematocrit and total protein on the higher end
- Dog is active, eating well, good coat, normal stool
- No fever, no weight loss, no vomiting or lethargy
- BUN elevated and creatinine also significantly elevated - creatinine rising meaningfully alongside BUN is not a diet effect, it's a kidney signal
- SDMA elevated - confirms reduced kidney filtration independent of diet
- ALT + ALP both significantly elevated alongside symptoms
- Platelet count sharply reduced, with fever or recent tick exposure
- Any cluster of abnormal values paired with clinical deterioration
Three Things Worth Doing Before Your Dog's Next Blood Test
Simple steps that make a real difference
Two Different Lenses. Same Dog.
A vet and a pet nutritionist are looking at the same animal from different angles. A vet brings clinical training, diagnostic skill, and the ability to identify and treat disease. A nutritionist brings understanding of how diet shapes the body's baseline over time - what "well-nourished" looks like metabolically, and how that differs from population averages built on other diets.
These perspectives aren't in tension. They're complementary. The best outcomes for dogs happen when both inform the picture.
The vets I've spoken to who are familiar with natural diets are not caught off guard by these blood shifts. Many of them are ahead of this - and they're the ones who ask what the dog eats before reviewing a panel, not after. If yours doesn't yet, this article is a starting point for that conversation.
- A note of exactly what your dog eats: brand, format, protein percentage
- How long they've been on this diet
- Your dog's previous blood panels if available, as a personal baseline
- Any specific markers you'd like explained in the context of their diet
UNDERSTOOD Dog-o-Meals contain 75%+ real animal protein. They're air-dried at 50–75°C - preserving enzymes, amino acid structures, and bioavailable nutrients that high-heat extrusion at 200°C+ destroys.
A dog on UNDERSTOOD for 6 months or more will likely show some of the dietary-shift markers described in this article — higher BUN, slightly elevated haematocrit, better total protein. That's not a side effect. It's what a well-nourished dog looks like.
UNDERSTOOD is AAFCO complete for dogs and FEDIAF complete for cats. Always formulated by a certified nutritionist, not reverse-engineered from a label.
Sources & References
- Dodds, W.J. & Wynn, S. Raw Diets and Bloodwork Results: Should You Be Concerned? Hemopet, 2025. hemopet.org
- Gow, A.G. et al. Effect of withholding food versus feeding on creatinine, SDMA, cholesterol, triglycerides in 100 healthy dogs. JVIM / PMC, 2023. pmc.ncbi.nlm.nih.gov
- Morgan, J. Differences in Lab Values for Raw Fed vs. Kibble Fed Dogs and Cats. Dr. Judy Morgan's Naturally Healthy Pets, 2025. drjudymorgan.com
- My Pet Nutritionist. Can Diet Cause Raised Liver Enzymes? 2025. mypetnutritionist.com
- Paws & Claws Animal Hospital. Understanding Your Animal's Veterinary Tests. pawsandclawsanimalhospital.com
- Daily Dog Food Recipes. Reconsidering Blood Urea Nitrogen Reference Ranges in Raw Fed Dogs. 2025. dailydogfoodrecipes.com
- Royal Canin Academy. How I Approach the Dog with Altered Hepatic Enzymes. academy.royalcanin.com
- Raw Essentials NZ. Blood Tests & Raw Feeding. rawessentials.co.nz
What Changes in Your Dog's Blood Work on a Natural Diet, and How to Read It With Your Vet
If your dog eats fresh, air-dried, or minimally processed food, some blood markers will look different from the printed "normal" range. This isn't cause for alarm. It's something worth understanding, so you and your vet can interpret results together.
This article doesn't argue that blood tests are unreliable, or that vets are interpreting things incorrectly. It does something more useful: it explains what genuinely changes in blood chemistry when a dog eats high-quality natural food, so that you can walk into your vet's clinic with better context — and have a more informed conversation.
The goal is a pet parent and vet on the same page. Not one correcting the other.
Why Your Dog's "Normal" May Not Be on That Lab Sheet
When a blood test comes back and certain values are flagged, the comparison point is always a reference range - the band of values that represents "typical healthy dogs." This range was established over decades of veterinary research.
Here's the context that's worth knowing: most of that research was conducted on dogs eating commercial dry kibble, because that's what the vast majority of dogs eat. That's not a flaw in the research. It's just what the data reflects.
Dry kibble is typically around 10% moisture, 30–60% carbohydrates, and uses mixed animal and plant protein sources processed at very high temperatures. A dog whose entire life has been spent eating that diet has a particular metabolic baseline - and that baseline became the reference standard.
Your dog on a fresh, air-dried, or raw diet is eating something genuinely different: higher animal protein, more moisture from food itself, fewer processed carbohydrates, and lower inflammatory load from additives and heat-damaged fats. Their body reflects that difference - including in blood chemistry.
Veterinary researchers Dr. Jean Dodds and Dr. Susan Wynn studied over 200 dogs across kibble-fed and naturally-fed groups and reached a clear conclusion: reference ranges for naturally-fed dogs need to be considered separately from those built on processed diets. [1] This isn't fringe opinion — it's a documented research finding that informs how progressive clinicians approach nutrition-aware blood panel reading.
What Actually Changes — and Why
Most blood values stay entirely consistent regardless of diet. The differences that show up in naturally-fed dogs are specific and predictable. Here's what to look out for, what drives each shift, and how a vet familiar with natural diets will read it.
How to read it: BUN on its own doesn't tell you much. A vet will look at BUN and creatinine together, alongside hydration status and whether the dog has any symptoms. An elevated BUN with a normal creatinine in a healthy, hydrated dog is almost always dietary.
Why this matters: This is exactly what makes creatinine the more reliable kidney marker for naturally-fed dogs. BUN rises because of diet, Creatinine doesn't. So if creatinine is significantly elevated alongside BUN, diet is no longer a sufficient explanation. That combination is what warrants investigation, not BUN alone.
How to read it: A mildly elevated ALT alongside normal ALP and normal bilirubin in an active, symptom-free dog is very rarely cause for immediate intervention. The right follow-up is bile acid testing, not alarm.
Important exception: A significant drop in platelets accompanied by fever, lethargy, or tick exposure history should always be investigated for tick-borne disease (Ehrlichiosis, Anaplasmosis). That's a separate matter from diet entirely.
| Marker | Typical on Kibble | On Natural Diet | What It Reflects |
|---|---|---|---|
| BUN | Moderate | Higher | More protein metabolism — dietary, not renal |
| Creatinine | Normal range | Largely stable | Not diet-driven — the reliable kidney signal |
| Haematocrit | Moderate | Higher | Better iron & B-vitamin absorption |
| ALT | Can be elevated | Mildly elevated possible | Read alongside ALP + Bilirubin, not alone |
| Platelets | Moderate | Slightly lower possible | Lower inflammatory baseline |
| Total Protein | Lower | Higher | Better amino acid availability |
| Glucose | Higher | Lower, stable | Fewer carbohydrates — metabolic advantage |
How to Look at a Panel — Clusters, Not Single Numbers
The most important shift in how you read your dog's blood work is moving from single-number thinking to pattern thinking. Real clinical concern almost always shows up across multiple markers simultaneously, and alongside physical symptoms.
Here are the clusters worth understanding:
For kidney health — look at all four together
BUN + Creatinine + SDMA + Urine Specific Gravity. The key distinction here is this: BUN rises on a high-protein diet. Creatinine largely doesn't — it's cleared by the kidneys through glomerular filtration and isn't meaningfully influenced by what the dog is eating. So on a natural diet, you'd expect BUN to be elevated while creatinine stays relatively stable. That's a dietary pattern. If creatinine is also climbing significantly alongside BUN, that combination can no longer be explained by diet — the kidneys aren't clearing it properly, which is a different matter entirely. SDMA is a newer, more sensitive marker that detects kidney dysfunction at 40% function loss — versus 75% for BUN alone — and is also unaffected by protein intake. [6] It's worth requesting specifically if kidney health is a concern.
For liver health — look at the full enzyme panel
ALT + ALP + Bilirubin together. A mildly elevated ALT with normal ALP and bilirubin in an active dog is not the same picture as ALT and ALP both rising significantly alongside lethargy or jaundice. If there's any genuine concern, bile acid testing (pre- and post-prandial) is the appropriate next step. [7]
And always factor in the dog in front of you
Energy. Appetite. Coat quality. Stool consistency. Muscle condition. These are the upstream signals. Blood values and physical presentation together tell a complete story. A number in isolation rarely does.
- BUN elevated, creatinine normal or slightly elevated, SDMA normal
- Haematocrit and total protein on the higher end
- Dog is active, eating well, good coat, normal stool
- No fever, no weight loss, no vomiting or lethargy
- BUN elevated and creatinine also significantly elevated - creatinine rising meaningfully alongside BUN is not a diet effect, it's a kidney signal
- SDMA elevated - confirms reduced kidney filtration independent of diet
- ALT + ALP both significantly elevated alongside symptoms
- Platelet count sharply reduced, with fever or recent tick exposure
- Any cluster of abnormal values paired with clinical deterioration
Three Things Worth Doing Before Your Dog's Next Blood Test
Simple steps that make a real difference
Two Different Lenses. Same Dog.
A vet and a pet nutritionist are looking at the same animal from different angles. A vet brings clinical training, diagnostic skill, and the ability to identify and treat disease. A nutritionist brings understanding of how diet shapes the body's baseline over time - what "well-nourished" looks like metabolically, and how that differs from population averages built on other diets.
These perspectives aren't in tension. They're complementary. The best outcomes for dogs happen when both inform the picture.
The vets I've spoken to who are familiar with natural diets are not caught off guard by these blood shifts. Many of them are ahead of this - and they're the ones who ask what the dog eats before reviewing a panel, not after. If yours doesn't yet, this article is a starting point for that conversation.
- A note of exactly what your dog eats: brand, format, protein percentage
- How long they've been on this diet
- Your dog's previous blood panels if available, as a personal baseline
- Any specific markers you'd like explained in the context of their diet
UNDERSTOOD Dog-o-Meals contain 75%+ real animal protein. They're air-dried at 50–75°C - preserving enzymes, amino acid structures, and bioavailable nutrients that high-heat extrusion at 200°C+ destroys.
A dog on UNDERSTOOD for 6 months or more will likely show some of the dietary-shift markers described in this article — higher BUN, slightly elevated haematocrit, better total protein. That's not a side effect. It's what a well-nourished dog looks like.
UNDERSTOOD is AAFCO complete for dogs and FEDIAF complete for cats. Always formulated by a certified nutritionist, not reverse-engineered from a label.
Sources & References
- Dodds, W.J. & Wynn, S. Raw Diets and Bloodwork Results: Should You Be Concerned? Hemopet, 2025. hemopet.org
- Gow, A.G. et al. Effect of withholding food versus feeding on creatinine, SDMA, cholesterol, triglycerides in 100 healthy dogs. JVIM / PMC, 2023. pmc.ncbi.nlm.nih.gov
- Morgan, J. Differences in Lab Values for Raw Fed vs. Kibble Fed Dogs and Cats. Dr. Judy Morgan's Naturally Healthy Pets, 2025. drjudymorgan.com
- My Pet Nutritionist. Can Diet Cause Raised Liver Enzymes? 2025. mypetnutritionist.com
- Paws & Claws Animal Hospital. Understanding Your Animal's Veterinary Tests. pawsandclawsanimalhospital.com
- Daily Dog Food Recipes. Reconsidering Blood Urea Nitrogen Reference Ranges in Raw Fed Dogs. 2025. dailydogfoodrecipes.com
- Royal Canin Academy. How I Approach the Dog with Altered Hepatic Enzymes. academy.royalcanin.com
- Raw Essentials NZ. Blood Tests & Raw Feeding. rawessentials.co.nz