Life-stage wellness: diagnostics
Why is laboratory testing important for my pet?
Veterinarians depend on diagnostics to help them understand the status of your pet's health. When your pet is sick, the results of laboratory tests can help the veterinarian confirm the presence of some illnesses and rule out others. The veterinarian may also re-run tests during the course of your pet's illness to track the course of the disease and the response to treatment.
When your pet is apparently healthy, your veterinarian may want to run certain laboratory tests to establish your pet's "baseline" values. Usually, these tests include a complete blood count (CBC) or packed cell volume (PCV), a biochemistry panel, a thyroid screen, a urinalysis, and sometimes faecal analysis. If your pet does become ill, the veterinarian can more easily determine if your pet's laboratory values are abnormal by comparing the baseline values to the current values.
How quickly will I know the results of the tests?
This will depend on the type of illness. In some cases, the laboratory tests will be sent to a commercial laboratory. These laboratories are equipped to provide more extensive testing than we can offer in the clinic. Results can usually be obtained within 24 - 48 hours. Laboratory tests performed in the clinic are usually for basic screening, and are quick, accurate and lower cost. We also can test in the hospital on an emergency basis and in these cases, results can be obtained usually in less than 1 hour, and in some cases minutes.
What does each laboratory test do?
There are several types of basic laboratory tests your veterinarian will use to evaluate wellness. Each one provides information concerning the true health of your pet.
Biochemistry Tests - Blood-chemistry panels measure electrolytes, enzymes, and chemical elements such as calcium and phosphorous. The information helps your veterinarian determine how various organs, such as the kidneys, pancreas, and liver, are currently functioning. The results of these tests help your veterinarian formulate an accurate diagnosis, prescribe proper therapy, and monitor the response to treatment. Further testing may be recommended based on the results of these tests.
Chemistry panels may also be recommended to obtain normal values, which can then serve as baseline data when the tests are run again at a later date. Differences between the baseline values and the subsequent values can help your veterinarian diagnose new problems.
- Liver (AST, ALT, ALP., T.Bil, GGT, Cholesterol, Proteins) - This group of tests helps evaluate various functions and health of the liver. Decreased liver function, inflammation, infection and neoplasia (cancer) of the liver and gall bladder may be detected by one or all of these tests.
- Kidney (BUN, Creatinine, Phosphorus, Albumin, Globulin) - These tests monitor the function and health of the kidneys. They are most helpful and sensitive for detecting kidney disease when combined with a urinalysis (see section 4).
- Pancreas (Glucose, Amylase, Lipase, Triglyceride) - These tests are abnormal when there is something wrong with the pancreas or carbohydrate metabolism (examples are diabetes mellitus and pancreatitis).
- Muscle and Bone -
- Calcium and Phosphorous are helpful in determining the health of bone metabolism.
- CPK and AST are abnormal with muscle damage, trauma or inflammation.
- Electrolytes (Sodium, Potassium, Chloride, Magnesium, Calcium, Phosphorus). These are important in monitoring the electrical, water balance and cellular health of the body.
Complete Blood Count (CBC) - This common test measures the number of red blood cells, white blood cells, and platelets. The numbers and types of these cells give the veterinarian information needed to help diagnose anaemia, infections, and leukaemia. A complete blood count also helps your veterinarian monitor your pet's response to some treatments.
Urinalysis - Laboratory analysis of urine can assist the veterinarian in the diagnosis of urinary-tract infections, diabetes, dehydration, kidney problems, and many other conditions.
Thyroid Function - As the name implies, these tests are useful in diagnosing malfunctions of the thyroid gland. Hypothyroidism (too little thyroid hormone) is common in dogs; whereas hyperthyroidism (too much thyroid hormone) is common in older cats.
Other tests that your veterinarian may advise after completion of the wellness exam:
Fine Needle Aspirates - When your pet has a lump or bump, your veterinarian may take a sample by using a hollow needle that withdraws cells and /or fluid form the bump. The sample is put on a slide and viewed with a microscope. The fine-needle aspirate is a quick way to diagnose infections and cancer and can also provide information about whether a tumour is malignant or benign. Your veterinarian uses that information to proceed with additional tests or treatment.
Cytology - A sample is put on a slide, stained and viewed with a microscope. Stained cytology is a quick way to diagnose infections and cancer and can also provide information about whether lesions or masses are benign or of concern.
Tests for Immunodeficiency Diseases - The veterinarian may recommend a test to determine whether or not your cat has contracted feline immunodeficiency virus or feline leukaemia virus.
Glaucoma Screen - Glaucoma is a leading cause of blindness in dogs and is caused by increased fluid pressure in the eye. Annual screening exams are advised especially for those pets that has a predisposition for eye disease. Glaucoma is diagnosed by measuring the intraocular pressure with a tonometer. This is usually done with local anaesthetic drops placed in your dog's eye.
Blood Pressure Monitoring – As in humans, high blood pressure is a concern for pets. The retina of the eye is especially at risk for blindness. Thyroid and kidney disease are important causes of high blood pressure and also progress more rapidly in the presence of high blood pressure. Blood pressure measurement is performed similarly to the way it is in humans. An inflatable cuff is fit snugly around the leg of the pet. Sometimes the base of the tail can be used.
ECG - An electrocardiogram is a test that checks for problems with the electrical activity of the heart. The ECG translates the heart's electrical activity into line tracings on paper, which are then reviewed by the veterinarian. The ECG is done to:
- Find the cause of symptoms of heart disease, such as dizziness, fainting, or rapid, irregular heartbeats.
- Find out if the walls of the heart chambers are too thick.
- Check how well medicines are working and whether they are causing side effects that affect the heart
- Check the health of the heart when other diseases or conditions are present, such as high blood pressure or diabetes.
Radiography - X-rays can be a valuable diagnostic tool that helps identify problems, including tumours, heart and lung disease, bladder stones, and osteoarthritis.
Ultrasound - An ultrasound is a non-invasive procedure similar to an x-ray. Most commonly used as a diagnostic tool to evaluate diseases of the heart, liver, pancreas, kidney, intestine, spleen, urinary bladder and other organs located in the abdomen.