Last Updated on June 28, 2021 by Julia Wilson
As a cat moves into middle-age and onward, wellness checks become essential. A physical examination will provide valuable information to a veterinarian, but what they can’t do is give a picture of everything that is happening on the inside; this is where diagnostic tests come into play.
Diagnosing age-related disorders means that it is easier to slow down progression, manage or even cure the disease. For example, clinical signs of kidney disease don’t become apparent until 70% of kidney function has been lost. The longer a disease progresses, the poorer the outcome which highlights the importance of diagnostic tests for cats as they age.
Common age-related diseases
- Chronic kidney disease
- Liver disease
- Heart disease
- Gum disease
During a wellness exam, the veterinarian will ask several questions which can help to assess the overall health of the cat.
- Have you noticed a change in litter box habits such as urinating more, going to the toilet outside the tray, blood in the urine or feces, diarrhea or constipation?
- Any changes to the cat’s eating habits, is the cat eating more or less than usual?
- What food does the cat eat?
- Changes to how much water the cat drinks?
- Is the cat moving around well? Have you noticed a reluctance to jump or stiffness upon waking?
- Does the cat take regular parasite control?
- Have you noticed any changes in behaviour?
- Any lumps and bumps, if so, where and how long have they been present?
What tests are necessary?
Performed on the clear/fluid portion of the blood to evaluate the functional capacity of several critical organs and systems, such as the liver and kidneys as well as glucose, sodium, potassium, cholesterol, enzymes such as aminotransferase (ALT) and creatinine.
Complete blood count
A series of tests that evaluates the cellular components of blood (red blood cells, white blood cells, and platelets). Vets often take this test to check for anaemia, infections, certain cancers and other health problems.
A urine sample is evaluated for its physical properties. Specific gravity, colour and clarity, and biochemically for pH, protein, glucose, bilirubin, and ketones, and microscopically for blood cells, crystals, casts (solid, tubular deposits) and bacteria. A Urinalysis can detect diseases such as diabetes, kidney disease and infections of the urinary tract.
T3 and T4 tests
Feline hyperthyroidism is a common disease caused by a benign hormone-secreting tumour of the thyroid gland. It is the most common endocrine disorder in cats and occurs most often in cats over ten years of age.
The thyroid gland is a butterfly-shaped gland located in the neck which secretes T3 and T4 hormones responsible for metabolism, growth, temperature and several organ functions. T4 (total T4) is the most common test which measures T4 concentrations in the blood. Medical conditions (especially chronic kidney disease), nutrition and medications can all affect T4 levels. 90% of symptomatic cats will have an elevation in T4 hormones, which is sufficient to diagnose hyperthyroidism.
If the T4 test is inconclusive, but the veterinarian suspects hyperthyroidism, then they will run a T3 test. T3 is the active thyroid hormone and accounts for 20% of all thyroid hormones. In some cases, the thyroid may still produce normal T4 levels, but there will be an increase in T3 levels.
A condition in which the force of the blood against the artery walls is too high, which poses a significant risk to many organs of the body such as the eyes, kidneys, brain, arteries, and heart. Between 20-60% of cats with chronic kidney disease also have high blood pressure; however, a recent study in the UK found that only 1.3% of cats had their blood pressure assessed. The study involved 347,889 and found 19.5% of cats had high blood pressure, which shows the problem is way under-diagnosed.
The veterinarian can measure the cat’s blood pressure during the examination, which is similar to how blood pressure is checked in people. If your veterinarian doesn’t routinely check the blood pressure, ask if they can do so.
What age should a cat start having tests?
Ideally, all cats should have routine bloodwork once a year as a part of their annual health examination, which will provide the veterinarian with baseline values to refer to each time the cat is evaluated. From seven years, the importance of diagnostics increases as the cat moves into middle-age and age-related diseases become a more significant factor.