Senior Dog Blood Work: What to Expect and What the Results Mean

Senior dog blood work is a snapshot of your dog’s internal health—it catches kidney disease, liver problems, diabetes, and other age-related conditions before symptoms appear. I started getting Cooper’s blood work done annually at age 7, and by his last panel, I could spot the patterns that told me something was changing.

Blood work isn’t just about finding disease. It’s about establishing a baseline when your dog is healthy so you have something to compare against later. That early detection window can add months or years to your dog’s life.

Why Senior Dogs Need Regular Blood Work

Dogs age faster than we do—much faster. A 7-year-old dog is roughly equivalent to a 50-year-old human, and organ function starts declining around this age even when everything looks normal from the outside.

The problem is that dogs are masters at hiding illness. Cooper was still running around the yard and eating normally when his blood work showed early kidney changes. By the time a dog shows outward symptoms like lethargy or loss of appetite, the disease has often progressed significantly.

Regular blood work for senior dogs (7+ years for most breeds, 5+ for giant breeds) allows your vet to:

• Detect organ dysfunction before it becomes critical
• Catch metabolic diseases like diabetes or thyroid issues early
• Monitor chronic conditions if your dog already has a diagnosis
• Screen for anemia or blood cell abnormalities
• Establish safe anesthesia protocols if your dog needs surgery or dental work

What’s Included in Senior Dog Blood Work

A standard senior panel typically includes two main components: a Complete Blood Count (CBC) and a Chemistry Panel. Some vets also include thyroid testing and urinalysis.

Complete Blood Count (CBC)

The CBC looks at your dog’s blood cells—red blood cells, white blood cells, and platelets. This test reveals:

• Red blood cell count: Anemia shows up here, which can signal internal bleeding, chronic disease, or bone marrow problems
• White blood cell count: Elevated levels suggest infection or inflammation; low levels can indicate immune system issues
• Platelets: Critical for blood clotting—low platelets can mean clotting disorders

Chemistry Panel

This is where organ function gets assessed. A typical chemistry panel tests 12-25 different values. The most important markers for senior dogs are:

• Kidney markers (BUN, creatinine, SDMA): Elevated levels indicate kidney disease—the most common age-related condition in senior dogs
• Liver enzymes (ALT, AST, ALP, GGT): High values can signal liver disease, Cushing’s disease, or medication side effects
• Glucose: Elevated glucose points to diabetes; low glucose can indicate liver disease or insulin-producing tumors
• Electrolytes (sodium, potassium, chloride): Imbalances affect heart and muscle function
• Total protein and albumin: Low levels suggest liver disease, kidney disease, or GI issues

Additional Tests

Many vets include these in senior panels:

• Thyroid (T4): Hypothyroidism is common in older dogs and causes weight gain, lethargy, and skin problems
• Urinalysis: Checks for urinary tract infections, kidney disease, and diabetes
• Urine protein-to-creatinine ratio (UPCR): Early kidney disease marker

What to Expect at the Vet

Blood work is quick and relatively stress-free for most dogs. Here’s the typical process:

Fasting: Your vet will usually ask you to withhold food for 8-12 hours before the appointment. This prevents false elevations in glucose and certain enzymes. Water is fine.

The blood draw: Takes about 2-3 minutes. The vet tech will usually draw from the jugular vein (neck), cephalic vein (front leg), or saphenous vein (back leg). Most dogs tolerate this well—I used to bring high-value treats and Cooper would barely notice.

Sample processing: Blood is divided into different tubes depending on the tests. Some clinics run tests in-house (results in 30-60 minutes), while others send samples to a lab (results in 1-2 days).

Cost: Expect to pay $100-$300 for a senior panel, depending on your location and what’s included. It’s worth every penny for the peace of mind.

Understanding the Results: Key Markers and What They Mean

Your vet will walk you through the results, but it helps to understand what you’re looking at. Blood work results show each value alongside a reference range—the normal range for healthy dogs.

Test	What It Measures	High Levels May Indicate	Low Levels May Indicate
BUN	Kidney function	Kidney disease, dehydration, high-protein diet	Liver disease, low-protein diet
Creatinine	Kidney function	Kidney disease, dehydration, muscle damage	Muscle loss, starvation
ALT	Liver enzyme	Liver disease, certain medications, Cushing’s	Rarely significant
ALP	Liver/bone enzyme	Cushing’s disease, liver disease, bone growth, steroids	Rarely significant
Glucose	Blood sugar	Diabetes, stress, Cushing’s	Insulinoma, liver disease, sepsis
Total Protein	Overall protein levels	Dehydration, chronic inflammation	Liver disease, kidney disease, GI disease, bleeding
T4	Thyroid hormone	Hyperthyroidism (rare in dogs)	Hypothyroidism

Important: One abnormal value doesn’t always mean disease. Stress, dehydration, recent meals, and even breed differences can affect results. That’s why vets look at the whole picture and often recommend retesting if something’s borderline.

Red Flags in Blood Work Results

Some findings warrant immediate attention:

Significantly elevated kidney values (BUN >80, creatinine >2.5): Suggests moderate to severe kidney disease. Your vet will likely recommend a renal diet, subcutaneous fluids, and more frequent monitoring.

Very high glucose (>250 mg/dL): Strongly suggests diabetes, especially if paired with excessive thirst and urination. Early diagnosis and insulin management make a huge difference.

Severe anemia (low red blood cells): Can indicate internal bleeding, immune-mediated disease, or toxin exposure. This needs immediate investigation.

Extremely elevated liver enzymes: May signal acute liver damage, toxin ingestion, or severe infection. Follow-up imaging and additional tests are usually needed.

When Cooper’s kidney values first came back elevated, they weren’t in the danger zone—his BUN was 35 (normal is up to 27) and creatinine was 1.6 (normal up to 1.4). My vet called them “early changes” and we started monitoring every 6 months instead of annually. That early catch gave us time to adjust his diet and slow the progression.

How Often Should Senior Dogs Get Blood Work?

The general recommendation is:

• Ages 7-9 (or 5-7 for giant breeds): Annual blood work
• Ages 10+ (or 8+ for giant breeds): Every 6 months
• Dogs on medications: Every 6 months minimum, or as recommended by your vet
• Dogs with chronic conditions: Every 3-6 months

I know blood work isn’t cheap, but it’s far less expensive than treating advanced disease. The cost of managing early-stage kidney disease is a fraction of what emergency treatment costs when a dog goes into kidney failure.

If cost is a barrier, ask your vet about basic vs. comprehensive panels. A basic panel might cost $80-$100 and still catches the major issues. Some clinics also offer senior wellness packages that bundle blood work with a physical exam at a discount.

Making Blood Work Part of Your Routine

I schedule Cooper’s blood work for the same month every year—October, right before his birthday. Having it on the calendar meant I never forgot, and having annual results to compare showed trends over time.

Ask your vet for a copy of the results to keep in a pet health record organizer. I keep all of Cooper’s old lab reports in a binder, and when we switched vets once, having that history was invaluable.

Also consider discussing senior dog supplements for kidney support with your vet if early changes appear, though always check with your vet before adding anything to your dog’s regimen.

Frequently Asked Questions

Does my dog need to fast before blood work?

Yes, most vets recommend withholding food for 8-12 hours before blood work. This prevents false elevations in glucose and certain enzymes. Water is fine and should be available. If your dog is diabetic or has other conditions that make fasting risky, ask your vet for specific instructions.

Can I get blood work done at a low-cost clinic?

Yes, low-cost clinics and mobile vet services often offer blood work at reduced prices. Just make sure they send samples to a reputable lab. The quality of the test matters more than the price. Also, you’ll still need a vet to interpret the results and recommend follow-up care.

What if my dog’s results are borderline abnormal?

Borderline results often warrant a retest in 2-4 weeks. Stress, dehydration, and recent activity can all skew results slightly. If the values are still elevated on a second test, your vet will likely recommend additional diagnostics like imaging or urine tests. Don’t panic over one borderline value—trends matter more than single data points.

Is blood work required before anesthesia for dental cleaning?

Yes, and for good reason. Anesthesia is processed by the liver and kidneys, so your vet needs to know those organs are functioning well before putting your dog under. Blood work also reveals anemia and clotting issues that could cause complications during surgery. This isn’t an upsell—it’s a safety measure.

Can blood work detect cancer in senior dogs?

Blood work can’t detect most cancers directly, but it can reveal abnormalities that warrant further investigation. For example, abnormal protein levels, anemia, or elevated calcium can be red flags. Some cancers cause changes in liver or kidney values. For cancer screening, your vet will rely more on physical exams, imaging, and sometimes specific cancer markers or biopsies.