Lab tests are an important part of your dog or cat’s routine checkups. We take a close-up look at some of the most common tests, and what they can tell you about your best friend’s health.

Whenever you take your dog or cat to the vet for a routine checkup, the veterinarian does lab tests to look for potential health problems. It’s a regular procedure, but have you ever wondered precisely what the vet is testing for, and what the results actually mean? This article will give you insight into some of the most common lab tests for dogs and cats, and how understanding them can keep your pet healthy and living longer.*

1. BUN/Creatinine/SDMA

BUN (blood urea nitrogen) is one of three blood tests for kidney function. It is a good screening test but not perfect since 60% to 70% of kidney function has to be destroyed before it elevates significantly. BUN is also affected by diet, exercise, and muscle mass, so results can be skewed due to factors unrelated to the kidneys.

Creatinine refers to an amino acid constituent of muscle protein. Like BUN, this test also doesn’t show a significant elevation unless 60% to 70% of kidney function is gone, and it can also be affected by diet, exercise, and muscle mass (but not as much as BUN). Blood profiles that incorporate only these two tests can accurately diagnose kidney disease once it has progressed to a later stage, but they are not so good for diagnosing very early disease.

This is why a third test called SDMA (symmetric dimethylarginine), which tests for the amino acid arginine, is recommended. SDMA levels elevate very early in the course of kidney disease – anywhere from 12 to 36 months before BUN and creatinine levels elevate – reflecting damage to only 25% of kidney damage versus 60% to 70%. From a functional medicine perspective, adding the SDMA test to the blood profile is extremely beneficial as we can diagnose kidney disease at a very early stage (Note: many veterinarians do not routinely test for SDMA.)

Other tests that can help diagnose pets with kidney failure include blood levels of phosphorus and calcium. Phosphorus in particular reveals the severity of kidney issues because it elevates when the kidneys are seriously damaged. Pets with elevated blood phosphorus levels and elevated levels of the kidney enzymes mentioned above are much harder to treat and have a poorer prognosis.

Adding the SDMA test to the blood profile is extremely beneficial as we can diagnose kidney disease at a very early stage.


ALT stands for alanine aminotransferase and ALP (also called SAP) for alkaline phosphatase. These two tests are useful for diagnosing problems of the liver, gallbladder, and adrenal glands. ALT increases whenever there is any damage or insult to the liver or gallbladder. Unfortunately, while ALT is a good test, it cannot tell us why the liver is damaged; other tests such as radiographs, ultrasound, and liver biopsy are needed to reveal the cause of ALT increases.

ALP can also increase when the liver or gallbladder are damaged; however, ALP most commonly increases when the adrenal glands are diseased, increasing their hormonal output, usually of cortisol. Pets with ALP increases have an adrenal disease that may progress to Cushing’s, a severe adrenal condition that at times requires chemotherapy (in addition to natural therapies) to be correctly treated.

Sadly, I see many pets who have been misdiagnosed with liver disease based on increased blood levels of the ALP enzyme. These pets really have adrenal disease and must be treated correctly. Treating them for liver disease (including doing surgery for a liver biopsy) can further injure or even kill them.

Fortunately, both liver and adrenal disease, when properly diagnosed, are easily treated with natural remedies. In my practice, most pets properly treated for adrenal disease never develop the more serious Cushing’s, again showing the importance of early lab testing.

3. T4/FT4

Because thyroid disease is so common in dogs and cats (dogs usually have low thyroid issues while cats have increased thyroid hormone disease), checking both Total T4 (TT4) and Free T4 (FT4) values is essential. Because hormonal testing costs more than a simple chemistry profile, many doctors leave these tests out (or only include the less accurate T4 test). When this happens, it poses a potential problem to the pet because thyroid disease can be overlooked. It also poses a problem to the pet owner who must pay for additional testing, which usually costs more than simply doing the correct blood profile (including both thyroid tests) upfront.

Because thyroid disease is so common in dogs and cats, checking both Total T4 (TT4) and Free T4 (FT4) values are essential.

Dogs and cats with thyroid disease can often be treated naturally without medications, especially when thyroid hormones are only slightly “off”. Functional medicine can restore normal hormone levels without the need for medication once thyroid disease is detected. Because thyroid disease resembles other conditions in clinical signs, I believe it’s always valuable to include thyroid testing for every pet.

How Often Should These Tests Be Done?

To maximize benefits to your dog or cat, and minimize costs to you, I recommend testing doing these tests every six to 12 months (pets under five years of age can be tested annually, whereas older animals benefit from twice-yearly testing). Once a problem is detected, more frequent blood testing (every three months) is helpful.

In Part 2 of this article (Aug-Sept 2017), we’ll examine additional important tests that are of benefit to dogs and cats, including fecal examination, urinalysis, radiographs, and ultrasound.

*In a prior article (“Antioxidants and your dog – what you need to know”, Feb-Mar 2017), I discussed the importance of testing for inflammation using CRP, TK, and vitamin D, so I won’t discuss those further here.

Addressing Slightly Abnormal Lab Results – Conventional vs. Holistic

Conventional doctors are trained to treat problems with drugs. However, there are no conventional treatments for dogs and cats with slightly abnormal lab results. Supportive treatment can be given, but only once the disease is severe.

Conversely, holistic doctors practicing functional medicine can treat pets (usually with herbs and homeopathics) before illness occurs, as soon as abnormalities are found in the process of wellness testing. Often, the subtle changes in lab values go away with this treatment, and future disease never occurs.

Considering Pet Insurance

If your dog or cat appears healthy, I encourage you to get pet insurance before his next checkup. In my practice, over 50% of the pets we test using the lab tests outlined in this article show abnormal findings – which are covered by pet insurance once the abnormality is noted. Don’t wait until a problem arises and then try to insure your pet. Play the odds that some tests will come back abnormal at some point, and get coverage before problems arise. It will save you money in the long run.