Be sure to read the other side of this debate, Doctor Debate: Wellness testing--More important than ever! by Dr. Fred Metzger.
Agree with Dr. Robbins? Agree with Dr. Metzger? Or do you have a completely different take? Click here to let everyone know what you think.
Today, a routine visit to the veterinarian is essentially a visit for numerous wellness tests. The idea is that problems caught
early can be treated and cured early. Although an earlier diagnosis generally has intuitive appeal, earlier might not always
be better. Wellness tests are like any other drug or medical procedure with potential risks that must be balanced with potential
Dr. David Robbins
The growing trend of "wellness testing" in veterinary medicine concerns me. Tests such as early detection panels, best care
panels, junior and senior panels, and preanesthetic panels are becoming a standard of care in our profession. Veterinarians,
many major veterinary organizations, pharmaceutical companies, national diagnostic laboratories, and even the media promote
Although the ability to do wellness testing has been around for years, it has only been recently that practitioners have emphasized
its role in veterinary medicine. I think there are four reasons for this.
First, wellness testing has financial rewards. Over the years, veterinarians have wrestled with innovative ways of increasing
their practice revenue. Wellness testing accomplishes this. Not only can wellness testing increase the utilization of other
testing modalities in a practice, it also helps reduce the burden of vaccines for practice profit. It is important for veterinary
practices to be financially healthy, but the way we achieve this should not supplant good medicine and should be in the best
interest of our patients.
Second, veterinarians often do wellness testing out of a need to protect themselves against lawsuits—so-called defensive medicine. Some veterinarians think it's always a good thing to look for things to be wrong. While many clients also demand routine
tests, they are often bolstered by advertisements, veterinary information online, and veterinarians. To some extent, veterinarians
have taught their clients to demand these things. And as a profession we've systematically exaggerated the benefits of early
diagnosis, which doesn't always improve survival, and, at the same time, we don't always tell our clients there might be downsides
Third, and most important, is that wellness testing "screens" for disease and, therefore, is good medicine. If we are using
the term wellness testing interchangeably with screening, then we need to examine the statistical merits of doing so. The optimal screening tests should be cost-effective, easy to
perform, and have high sensitivity (correctly detect most patients with a disease) and specificity (correctly identify most
patients that do not have a disease). It is also important to realize that normal test values are usually arbitrarily defined
as those occurring within two standard deviations from the mean, thereby ensuring that 5% of healthy pets that have a single
screening test will have an abnormal result. As more tests are ordered, the likelihood of a false positive result increases.
Therefore, a screening panel containing 20 independent tests in a patient with no disease will yield at least one abnormal
result 64% of the time.
Then there is the lead-time bias phenomenon.1 This bias refers to a spurious increase in longevity associated with screening. In other words, the screening test could
discover a disease before the patient feels ill, but it does not extend the patient's life. This early detection can artificially
inflate survival time by moving up the diagnosis date, making the test appear to be useful even though mortality doesn't change.
And what about the scientific evidence in support of wellness testing being a good disease screening tool? In human medicine,
the literature is replete with research showing the flaws with wellness testing.2-5 But in veterinary medicine there is a lack of evidence-based research showing that patients benefit from wellness testing.
Recently, two studies in veterinary medicine addressed the issues of wellness testing. Both studies looked at preanesthetic
testing and whether the test results affected the way we anesthetize patients. The first study, out of Germany, concluded,
"The changes revealed by preoperative screening were usually of little clinical relevance and did not prompt major changes
to the anesthetic technique."6 The second study, out of South Africa, concluded that 1) screening of geriatric patients is important and that subclinical
disease could be present in nearly 30% of these patients, and 2) the value of preanesthetic screening in veterinary anesthesia
still needs to be evaluated in terms of appropriate outcome variables.7 So based on two studies, at least one type of wellness testing (preanesthetic) may not be justified.