Senior Blood Testing: What We Look For and Why It Matters

When a pet reaches their senior years, a physical examination tells us a great deal. We can feel the abdomen, listen to the heart, assess mobility and muscle condition, check teeth, and note coat and skin changes. But there is a whole layer of information that a physical exam simply cannot access.

Blood and urine testing is how we see inside.

Senior pets can look and feel perfectly well while something is quietly developing. Kidney disease, thyroid dysfunction, early diabetes, anaemia, liver changes: all conditions that often produce no outward signs until they are well advanced. Testing is how we find them before that point.

When do we recommend a senior blood panel?

We recommend a senior blood and urine panel at least once a year for pets over seven, with twice-yearly general health exams for older animals or those managing known health conditions.

For cats over ten, we recommend annual thyroid testing as a standard inclusion, given how common hyperthyroidism is in older cats and how well it responds to early detection.

What does the panel include?

Full blood count (FBC)

This looks at your pet's red blood cells, white blood cells, and platelets. It helps us identify anaemia (low red blood cell count), infection, inflammation, and some cancers. A drop in red blood cell count, even without obvious symptoms, is worth investigating.

Biochemistry panel

The biochemistry panel gives us a view of organ function. It includes:

• Kidney markers (creatinine, BUN, and SDMA). SDMA is a particularly valuable kidney marker because it can detect kidney disease earlier than creatinine alone. This is where we often pick up early-stage kidney disease in cats and dogs who are still eating, drinking, and behaving normally.
• Liver enzymes (ALT, ALP, GGT). Elevated liver enzymes can point to liver disease, but also to changes in other organs that stress the liver secondarily. Context matters, and we interpret these alongside the rest of the panel.
• Blood glucose. Diabetes mellitus is more common in older pets than many owners realise. Elevated glucose with corresponding clinical signs points us toward a diagnosis quickly.
• Calcium and electrolytes. These give us information about parathyroid function, some cancers, and nutritional balance.

Thyroid level (T4)

This is primarily run for cats over ten, where hyperthyroidism is one of the most common conditions we diagnose. An overactive thyroid often mimics normal ageing, which means it goes undetected for longer than it should. Symptoms include weight loss despite a good appetite, increased thirst, restlessness, and sometimes a faster heart rate. T4 is simple to run and catches it early.

We also check thyroid levels in dogs when hypothyroidism (an underactive thyroid) is suspected, particularly in breeds with a known predisposition.

Urinalysis

Urine tells us a great deal that blood alone misses. We look at:

• Concentration. Dilute urine in an older pet can be one of the first signs of kidney disease or diabetes.
• Protein levels. Protein in the urine that should not be there points to kidney stress, and catching this early is important.
• Cells, casts, and bacteria. These indicate infection, inflammation, or structural changes in the urinary tract.
• Glucose. Glucose in the urine alongside elevated blood glucose confirms a diabetes diagnosis.

What happens after the results?

In most cases, a senior panel comes back with results that are broadly normal, or with minor changes that we monitor over time rather than treat immediately. That is actually useful information: it sets a baseline we can compare future results against.

When something significant does show up, early detection almost always means more options. Kidney disease caught at stage one responds very differently to kidney disease caught at stage three. We can often make meaningful changes to diet, medication, and monitoring that genuinely extend the time your pet feels well.

What the panel does not replace

Blood and urine testing works alongside a physical examination, not instead of one. We interpret the numbers in the context of what we find on the table. An elevated kidney marker in a pet who is otherwise bright, eating well, and normal weight tells a different story from the same number in a pet who has lost condition and is drinking more than usual.

This is also why we ask you about what you have noticed at home. You see your pet every day. Changes in drinking, appetite, energy, and sleep patterns are often the first signs of something developing, and they matter.

Thriving Pets Wellness Plan members

The Thriving Pets Wellness Plan is worth knowing about if you have a senior pet. Plan members receive unlimited consultations with $75 back on every consult throughout the year, as well as up to $100 off any blood work once a year. For older pets who benefit from regular visits and routine testing, those savings add up meaningfully over time.

Not yet on a plan? Take a look at the savings calculator at thrivingpets.com.au/thriving-pets.

Book a senior health check

Call Middle Brighton Vet on (03) 9592 9811 or book online. We are on Hampton Street in Brighton, open Monday to Friday 8am to 7pm and Saturday 8am to 2pm. If your pet is seven or older and has not had a comprehensive health check in the past year, it is worth getting one on the books.