Understanding Your Senior Dog’s Bloodwork
A results printout full of abbreviations and arrows isn’t much use if you don’t know what any of it means. Here’s a plain-English walkthrough of what actually shows up on a senior wellness panel.
This is a guide for understanding what your vet is looking at — not for self-diagnosing from a printout. A single abnormal value rarely tells the whole story; your vet reads the pattern, not one number in isolation.
The Two Core Tests
A standard senior panel covers two main pieces: a CBC (Complete Blood Count), which looks at red cells, white cells, and platelets, and a chemistry panel, which covers organ function, electrolytes, proteins, and blood sugar. Together they’re why AAHA recommends senior dogs get screened every 6-12 months — quiet, early changes are much easier to catch against a baseline than to notice from symptoms alone.
The CBC, in Plain English
| Marker | High usually means | Low usually means |
|---|---|---|
| RBC / HCT / Hgb | Dehydration (blood is more concentrated) | Anemia — chronic disease, blood loss, kidney disease |
| WBC / neutrophils | Infection, inflammation, or stress | Marrow suppression or overwhelming infection |
| Lymphocytes | Immune stimulation, chronic inflammation | Stress response, immune suppression |
| Platelets | Often reactive to inflammation | Clotting risk — worth prompt attention, especially with bruising or nosebleeds |
Kidney Markers: Why SDMA Changed the Game
Creatinine has been the traditional kidney marker, but it has a real blind spot: it’s affected by muscle mass, so a frail senior dog can have meaningful kidney disease while creatinine still looks “normal.” IDEXX’s own interpretation guidance notes SDMA isn’t affected by muscle mass the same way, and can detect kidney function loss earlier than creatinine typically does.
| SDMA range | What it suggests |
|---|---|
| 0-14 µg/dL | Normal reference range for adult dogs |
| 15-19 µg/dL | Mildly elevated — worth monitoring |
| 20+ µg/dL | Warrants urinalysis and follow-up to assess kidney function |
A rising BUN with normal creatinine and SDMA often points toward something like dehydration or diet rather than kidney disease. A persistent rise in creatinine and/or SDMA together is the pattern that’s actually concerning for true kidney dysfunction.
Liver Markers
ALT reflects liver cell injury directly. ALP can rise with cholestasis, steroid exposure, or Cushing’s disease — and mild ALP elevation is genuinely common in older dogs on its own, though persistent or rising levels alongside symptoms shouldn’t be waved off as “just age.” GGT helps clarify whether a bile duct problem is contributing when ALP is elevated. Bilirubin becomes more concerning when it rises alongside other liver markers or anemia.
Pancreatic and Metabolic Markers
Amylase and lipase are nonspecific — an elevated reading doesn’t automatically mean pancreatitis. If pancreatitis is genuinely suspected, Spec cPL is the more pancreas-specific test, which our pancreatitis guide covers in more depth. Glucose that’s elevated can point toward diabetes, stress, or other endocrine disease, while fructosamine reflects average blood sugar over roughly the past 1-3 weeks — useful for tracking known diabetes rather than a one-off diagnosis, as covered in our glucose monitoring guide. A standard senior panel doesn’t automatically include thyroid values, but if unexplained weight gain or low energy comes up alongside these results, that’s usually the point where a vet adds TT4, free T4, or TSH — our hypothyroidism guide walks through what those specific tests mean.
Proteins and Electrolytes
| Marker | Worth knowing |
|---|---|
| Albumin | Low levels can point to protein loss through the gut or kidneys, or reduced liver production |
| Globulin | High levels often reflect chronic inflammation or immune stimulation |
| Phosphorus | Elevated levels matter more in seniors — often paired with kidney markers for a fuller picture |
| Sodium/Potassium | Help assess hydration, adrenal function, and kidney status together |
Questions Worth Asking at the Appointment
- Ask “Is this change mild, moderate, or something to act on now?”
- Ask “Could dehydration, diet, or muscle loss explain this instead of disease?”
- Ask “Do these values warrant a urinalysis, blood pressure check, or imaging?”
- Ask “Should we recheck in a few weeks, or is 6 months still reasonable?”
FAQ
What’s the difference between creatinine and SDMA?
Both reflect kidney function, but SDMA isn’t affected by muscle mass the way creatinine is, so it can catch kidney decline earlier — particularly useful in a frail or muscle-wasted senior dog where creatinine alone might look deceptively normal.
My dog’s ALP is a little high — should I be worried?
Mild ALP elevation is genuinely common in older dogs and isn’t automatically concerning on its own. Persistent or rising levels, especially alongside symptoms, are what warrant a closer look.
Does elevated lipase mean my dog has pancreatitis?
Not necessarily — lipase and amylase are nonspecific. A Spec cPL test is more pancreas-specific if pancreatitis is genuinely suspected clinically.
The Bottom Line
No single number on a bloodwork panel tells the whole story — your vet is reading the pattern across values, alongside your dog’s history and exam findings. Knowing roughly what each marker reflects makes the conversation at your next senior wellness visit a lot less like decoding a foreign language.
This article is for informational purposes only and isn’t a substitute for veterinary diagnosis or treatment. Always discuss bloodwork results directly with your veterinarian.