Why Senior Wellness Bloodwork Matters
Senior wellness bloodwork is one of the most useful preventive interventions in canine medicine. Many diseases develop insidiously and produce no obvious clinical signs until well-established:
- Chronic kidney disease — often silent until 70%+ of renal function lost
- Cushing’s disease — signs often attributed to “aging” for years
- Hypothyroidism — gradual weight gain, lethargy, hair loss
- Hepatic disease — enormous reserve masks early disease
- Neoplasia — often detected on routine senior bloodwork
- Diabetes mellitus — earlier detection improves long-term outcomes
- Anaemia of chronic disease — flags underlying condition
This calculator interprets common blood values against typical reference ranges and flags patterns suggesting specific diseases.
When To Run Senior Bloodwork
Standard senior wellness recommendations:
| Age (size-adjusted) | Frequency |
|---|---|
| From senior threshold (toy/small 10y, medium 9y, large 7y, giant 6y) | Annual |
| From geriatric threshold (typically senior + 3 years) | Every 6 months |
| Diagnosed chronic disease | As directed by vet |
| Pre-anaesthetic | Always for senior dogs |
The Standard Senior Panel
A typical senior panel includes:
CBC (Complete Blood Count)
- PCV / haematocrit — anaemia / polycythaemia
- WBC + differential — inflammation, infection, stress
- Platelets — bleeding risk, tick-borne disease markers
Biochemistry
- ALT, ALP, GGT — hepatobiliary
- BUN, creatinine — kidney
- Glucose — diabetes
- Total protein, albumin — hydration, hepatic synthesis, GI/renal losses
- Electrolytes — Na, K, Cl, sometimes phosphorus, calcium
Endocrine
- Total T4 — thyroid screen (less sensitive than fT4ED + cTSH)
- Sometimes basal cortisol (Cushing’s / Addison’s screen)
Urinalysis
- Urine specific gravity (USG) — concentrating ability
- UPC ratio — proteinuria
- Sediment — cells, casts, crystals
- Culture — for symptomatic or recurrent UTI
Blood Pressure
Often overlooked but critical — hypertension common in CKD, Cushing’s, hyperthyroidism (rare in dogs).
Interpreting Common Values
ALT (Alanine Transferase)
Hepatocellular enzyme — leaks from injured hepatocytes.
| ALT (U/L) | Interpretation |
|---|---|
| <100 | Normal |
| 100-200 | Mild elevation — many causes |
| 200-500 | Significant — hepatic disease investigation |
| >500 | Markedly elevated — urgent workup |
Causes of elevation: chronic hepatitis, acute toxic insult (paracetamol, xylitol, NSAIDs, phenobarbital, prednisolone), neoplasia, lipidosis, breed-specific (Bedlington copper-storage).
ALT measures INJURY, not function. End-stage chronic hepatitis can have normal ALT because few hepatocytes remain to leak enzymes.
ALP (Alkaline Phosphatase)
Multiple isoenzymes: liver, bone, steroid-induced.
| ALP (U/L) | Interpretation |
|---|---|
| <150 | Normal |
| 150-300 | Mild — many causes |
| 300-1000 | Significant — workup |
| >1000 | Marked — classic for Cushing’s disease |
Causes: cholestasis, steroid effect (oral or topical corticosteroids; endogenous cortisol in Cushing’s), bone disease in growing dogs, breed variation (Scottish Terrier classically very high ALP), neoplasia.
Isolated elevated ALP in a senior dog is the classic Cushing’s screening flag. See PuppaDogs Cushing’s Pre-Test Calculator.
Creatinine
Kidney function — by-product of muscle metabolism.
IRIS CKD staging (in stable, hydrated dog):
| Creatinine (mg/dL) | Creatinine (μmol/L) | IRIS Stage |
|---|---|---|
| <1.4 | <125 | Normal |
| 1.4-2.8 | 125-249 | Stage 2 |
| 2.9-5.0 | 250-439 | Stage 3 |
| >5.0 | >440 | Stage 4 |
Stage 1 disease (creatinine still normal) detected by SDMA elevation. See PuppaDogs IRIS Calculator.
Always rule out pre-renal causes (dehydration) and post-renal (urinary obstruction) before assuming chronic kidney disease. Repeat in 2-3 weeks in a hydrated dog to confirm chronic.
BUN / Urea
Combination of dietary protein metabolism, hepatic function, and renal clearance.
| BUN (mg/dL) | Interpretation |
|---|---|
| <7 | LOW — hepatic insufficiency, low-protein diet, PSS |
| 7-25 | Normal |
| 25-40 | Mildly elevated |
| 40-80 | Significantly elevated — investigate |
| >80 | Severe azotaemia |
Disproportionate elevation (high BUN with normal/mildly elevated creatinine) = GI bleeding (BUN absorbed from digested blood), dehydration, high-protein diet.
Low BUN = hepatic insufficiency (reduced urea cycle), portosystemic shunt — check bile acids.
PCV / Haematocrit
Red blood cell concentration.
| PCV (%) | Interpretation |
|---|---|
| <20 | SEVERE anaemia |
| 20-30 | Moderate anaemia |
| 30-37 | Mild anaemia |
| 37-55 | Normal |
| >55 | Elevated — dehydration most common; polycythaemia rare |
Anaemia workup: reticulocyte count (regenerative vs non-regenerative), blood smear, coagulation panel, abdominal ultrasound.
WBC (White Blood Cells)
Inflammation / infection / stress marker.
| WBC (×10⁹/L) | Interpretation |
|---|---|
| <4 | Leukopenia — viral, bone marrow, severe sepsis |
| 4-17 | Normal |
| 17-30 | Leukocytosis — inflammation, infection, stress |
| >30 | Marked — significant infection, leukaemia |
Differential count clarifies cause (neutrophilia for inflammation/infection; eosinophilia for parasites/allergy; lymphocytosis for some neoplasias).
Platelets
Bleeding risk marker + tick-borne disease screening.
| Platelets (×10⁹/L) | Interpretation |
|---|---|
| <50 | SEVERE thrombocytopenia — bleeding risk |
| 50-150 | Thrombocytopenia |
| 150-500 | Normal |
| >500 | Thrombocytosis — reactive most common |
Thrombocytopenia is the hallmark of canine ehrlichiosis, anaplasmosis, and Rocky Mountain spotted fever. Always SNAP 4Dx in thrombocytopenic dog in endemic regions. See PuppaDogs Tick-Borne Disease Calculator.
Total T4 (Thyroid)
Screening for hypothyroidism (common in dogs) and hyperthyroidism (rare in dogs).
| T4 (μg/dL) | Interpretation |
|---|---|
| <1.0 | LOW — suggestive of hypothyroidism, but NOT diagnostic |
| 1.0-4.0 | Normal |
| >4.0 | High — hyperthyroidism rare in dogs; consider thyroid carcinoma, supplementation, error |
Sick euthyroid syndrome — concurrent illness, glucocorticoids, stress all lower T4 without true hypothyroidism. Always confirm low T4 with free T4 by ED + canine TSH before diagnosing hypothyroidism. See PuppaDogs Hypothyroidism Calculator.
Glucose
Diabetes mellitus screening + hypoglycaemia detection.
| Glucose (mg/dL) | Glucose (mmol/L) | Interpretation |
|---|---|---|
| <60 | <3.3 | HYPOGLYCAEMIA — emergency |
| 60-150 | 3.3-8.3 | Normal |
| 150-250 | 8.3-13.9 | Mild hyperglycaemia |
| >250 | >13.9 | DIABETES MELLITUS (with urine glucose) |
Hypoglycaemia in adult dogs is a vet emergency — insulinoma, sepsis, hepatic failure, Addison’s, paraneoplastic. Feed corn syrup on gums while transporting.
Sustained hyperglycaemia + glucosuria = diabetes. See PuppaDogs Insulin Calculator and DKA Recognition.
Total Protein And Albumin
Hydration, hepatic synthesis, GI/renal protein losses.
| Value | Interpretation |
|---|---|
| Total protein high (>8) | Dehydration; chronic ehrlichia (hyperglobulinaemia); rare myeloma |
| Albumin low (<2.5) | Hepatic insufficiency, protein-losing nephropathy (UPC), protein-losing enteropathy, severe inflammation |
| Albumin very low (<2.0) | OEDEMA risk |
Common Disease Patterns
Azotaemia (Elevated Creatinine + BUN)
Workup:
- Urinalysis — USG <1.030 = renal; >1.030 = pre-renal
- UPC for proteinuria
- Blood pressure
- Abdominal ultrasound
- SDMA for early CKD
Hepatopathy (Elevated ALT + ALP)
Workup:
- Bile acids (the specific liver function test)
- Abdominal ultrasound
- Coagulation panel
- Sometimes liver biopsy
- Breed-specific consideration — copper-storage hepatopathy in Bedlington/Westie/Skye/Doberman/Lab
Cushing’s Pattern (High ALP + Clinical Signs)
Disproportionately elevated ALP with relatively normal ALT in a senior dog + PU/PD, polyphagia, pot belly, alopecia = Cushing’s pre-test probability high.
Confirmatory tests: ACTH stim or LDDS. See PuppaDogs Cushing’s Calculator.
Tick-Borne Disease Pattern (Anaemia + Thrombocytopenia)
Workup:
- SNAP 4Dx (ehrlichia, anaplasma, lyme, heartworm)
- PCR for specific pathogens
- Coagulation panel (DIC consideration)
- See PuppaDogs Tick-Borne Disease Calculator
Hypothyroidism Pattern
Low T4 + hypercholesterolaemia + mild non-regenerative anaemia in a middle-aged-to-older predisposed breed (Doberman, Golden, Cocker, Boxer) = high pre-test probability for hypothyroidism.
Confirm with: free T4 by ED + cTSH. See PuppaDogs Hypothyroidism Calculator.
Honest Caveats
- Reference ranges vary slightly between laboratories — use your specific lab’s ranges where possible
- Single values out of range may be incidental — patterns of multiple abnormalities matter more
- Always interpret in clinical context — bloodwork is one piece of the picture
- Repeat suspicious values in 2-4 weeks in stable conditions
- Discuss results with your vet rather than acting on calculator output alone
- Sick euthyroid syndrome, breed variations, stress, recent medications all affect results
- This calculator is a reference and screening tool, not a diagnostic instrument
What To Ask Your Vet
When discussing abnormal bloodwork:
- “Are these findings consistent with my dog’s clinical signs?”
- “Should we repeat the test, or are they significant enough to act on immediately?”
- “What’s the next step — imaging, additional bloods, specialist referral?”
- “Could any of my dog’s medications be affecting these results?”
- “What’s the realistic prognosis and treatment plan?”
Conclusion
Senior wellness bloodwork is one of the most valuable preventive interventions in canine medicine — many diseases (CKD, Cushing’s, hypothyroidism, hepatic disease, neoplasia, diabetes) are detected before clinical signs develop and respond better to early treatment. Pattern recognition matters more than isolated abnormalities — azotaemia + low USG = CKD; high ALP + clinical signs = Cushing’s pattern; anaemia + thrombocytopenia = tick-borne disease workup. Annual senior panels from breed-size-adjusted senior age, every 6 months from geriatric, gives the best chance of early detection. Always discuss results with your vet for context-appropriate interpretation.
Frequently Asked Questions
What blood tests should my senior dog have?
Standard senior wellness panel: CBC (PCV, WBC differential, platelets); BIOCHEMISTRY (ALT, ALP, GGT, BUN, creatinine, glucose, total protein, albumin, electrolytes); ENDOCRINE (total T4, sometimes basal cortisol); URINALYSIS with UPC ratio and culture if needed; BLOOD PRESSURE measurement. Frequency: ANNUAL from senior threshold (toy/small breeds 10y, medium 9y, large 7y, giant 6y); EVERY 6 MONTHS from geriatric (typically senior + 3 years); always pre-anaesthetic for senior dogs.
What does high ALT mean in dogs?
ALT (alanine transferase) elevation indicates HEPATOCELLULAR INJURY (damaged hepatocytes leaking enzyme). Mild (100-200 U/L): obesity vacuolar hepatopathy, drug effect (NSAIDs, phenobarbital, prednisolone), recent illness, breed variation. Significant (200-500): chronic hepatitis, hepatic neoplasia, lipidosis. Marked (>500): acute hepatic injury (paracetamol/xylitol toxicity, severe inflammation), urgent workup. Important: ALT measures INJURY not FUNCTION – end-stage chronic hepatitis can have normal ALT with few remaining hepatocytes. Confirm with bile acids (specific function test) + ultrasound + sometimes biopsy.
What does high ALP mean in dogs?
ALP (alkaline phosphatase) has multiple isoenzymes – liver, bone, STEROID-INDUCED. Mild elevation common in older dogs (vacuolar hepatopathy, drug effect, breed variation – Scottish Terriers classically very high). Marked elevation (>1000 U/L) in senior dog is CLASSIC FOR CUSHING’S DISEASE (steroid-induced isoenzyme); other causes: cholestatic disease, bone disease, recent corticosteroid administration (oral OR topical), neoplasia. Combined with PU/PD, polyphagia, pot belly, alopecia raises Cushing’s pre-test probability substantially – ACTH stim or LDDS confirms.
How is kidney disease diagnosed by bloodwork?
IRIS CKD staging based on stable creatinine (in hydrated dog): Stage 1 normal creatinine but elevated SDMA; Stage 2 creatinine 1.4-2.8 mg/dL (125-249 umol/L); Stage 3 creatinine 2.9-5.0 mg/dL (250-439 umol/L); Stage 4 creatinine >5.0 mg/dL (>440 umol/L). Substaging by PROTEINURIA (UPC ratio) and BLOOD PRESSURE. Always rule out pre-renal causes (dehydration) before diagnosing chronic. Repeat in 2-3 weeks in hydrated dog to confirm chronic. Urinalysis with USG critical – <1.030 = renal; >1.030 = pre-renal. SDMA earlier detection than creatinine.
What is sick euthyroid syndrome in dogs?
Sick euthyroid syndrome (non-thyroidal illness syndrome) is when any concurrent illness, glucocorticoid administration, or severe stress SUPPRESSES total T4 into the hypothyroid range WITHOUT true hypothyroidism. Examples: acute or chronic illness (sepsis, neoplasia, organ disease), oral or topical steroids, phenobarbital, sulfa antibiotics. Total T4 returns to normal once underlying illness is treated. This is the main reason TOTAL T4 ALONE has many false positives for hypothyroidism – free T4 by equilibrium dialysis + canine TSH is the gold standard combination for diagnosis.
What does anaemia and low platelets mean together in a dog?
ANAEMIA + THROMBOCYTOPENIA combination is concerning – workup: (1) TICK-BORNE DISEASE – ehrlichiosis, anaplasmosis, Rocky Mountain spotted fever; SNAP 4Dx test essential in endemic regions. (2) IMMUNE-MEDIATED HAEMOLYTIC ANAEMIA with concurrent ITP (Evans syndrome). (3) BONE MARROW SUPPRESSION – drugs (chloramphenicol, oestrogens), chronic disease, neoplasia (lymphoma, leukaemia). (4) DIC (disseminated intravascular coagulation) – check coagulation panel; severe sepsis, neoplasia, immune disease can cause. (5) SPLENIC DISEASE – mass, torsion, sequestration. Urgent workup including SNAP 4Dx + coagulation + ultrasound.
Related PuppaDogs Calculators
Continue building your dog’s personalised care plan with these related PuppaDogs calculators:
- Dog Pregnancy / Whelping Due-Date Calculator
- Puppy Weight Predictor (Adult Weight Calculator)
- Heatstroke Risk Calculator for Dogs
- Bloat (GDV) Risk Calculator for Dogs
- Dog Life Expectancy Calculator (Breed, Body Condition, Lifestyle)
- Spay/Neuter Timing Calculator for Dogs (Breed-Specific)
References & Further Reading
The dosing ranges and safety information on this page are drawn from the following veterinary references. Always defer to your own veterinarian and the manufacturer’s label for your specific product.
- International Renal Interest Society (IRIS). CKD staging guidelines. iris-kidney.com.
- Ettinger SJ, Feldman EC, Cote E. Textbook of Veterinary Internal Medicine, 8th ed. Elsevier – clinical pathology chapters.
- Latimer KS, Mahaffey EA, Prasse KW. Duncan and Prasse’s Veterinary Laboratory Medicine: Clinical Pathology, 5th ed. Wiley-Blackwell.
- AAHA Senior Care Guidelines 2023.
- Plumb’s Veterinary Drug Handbook – reference ranges and interpretation.
- Mooney CT. Canine hypothyroidism: a review of aetiology and diagnosis. New Zealand Veterinary Journal.
- PuppaDogs. IRIS Kidney Disease Calculator, Cushing’s Calculator, Hypothyroidism Calculator. puppadogs.com.
