The case for pet wellness and routine monitoring — A comment

Dear Editor,

I read with interest your editorial in the December 2012 issue of The CVJ addressing an important topic for our profession, namely, pet wellness issues and diagnostic testing. As a veterinary clinical pathologist and clinical research scientist for nearly 50 years, much of my career has been dedicated to screening healthy animals of several species in comparison to those with inherited and acquired disorders. From this work and that of others during the 1970–1990 period came the data to support age-, sex-, and breed type-related norms for most of the clinical pathology reference ranges that are or should be applied today in assessing wellness and disease, especially within and between species, breed types and with aging (1).

In my experience, wellness screening on a regular annual or biannual basis for companion animals is important and does lead to early diagnosis and the possibility of successful intervention. Further support for this conclusion comes from a study done in 1998–1999 by Bruyette et al (2) at VCA West Los Angeles Animal Hospital.

Apparently healthy dogs (n = 90) and cats (n = 100), all over 7 years of age were studied. They had no underlying medical condition or treatment known to alter clinical laboratory values. After a thorough historical review, the animals underwent a general physical examination and laboratory tests including a CBC, serum chemistry profile, T4, urine cortisol:creatinine ratio (UCCR, dogs only), and complete urinalysis (cystocentesis samples). Only animals with a normal physical examination were selected (2).

Dogs

Increased ALP was seen in 15 (17%) dogs. Of these, 4 had increased UCCR, and 3 of them had abnormal low-dose dexamethasone suppression (LDDS) tests of pituitary-dependent hyperadrenocorticism. In 26 (29%) dogs, total T4 values were below normal. Eleven were re-evaluated and 9 were diagnosed with hypothyroidism based on low free T4 by equilibrium dialysis values. Eleven (11%) of the dogs had bacteriuria and pyuria. Four were also azotemic, in the absence of clinical dehydration, consistent with possible pyelonephritis. Urine specific gravities of 2 of them were 1.026 and 1.015, and both had positive urine cultures. This highlights the importance of performing a routine urinalysis, preferably on urine collected by cystocentesis, as part of the routine health assessment.

Cats

Elevated T4 was noted in 6 (16%), but a thyroid nodule was palpable in only 1 of them. Nine cats were azotemic based on elevations in blood urea nitrogen (BUN) and creatinine in the absence of clinical dehydration. Five of them had urine specific gravity below 1.035. One cat was diagnosed with diabetes mellitus based on persistent hyperglycemia and glucosuria.

The study concluded that the importance of routine veterinary visits and diagnostic laboratory screening becomes even greater as pets age. The overall prevalence of disease found in these apparently healthy dogs and cats was one of the most valuable findings. Despite the fact that these animals were not being treated for any underlying medical problems, clinically significant disease was found in more than 20% of the canine population and more than 17% of the feline population (2).