It is commonplace for veterinary clinics to recommend, or even require, pre-anesthetic blood work (PABW) for their young and healthy patients. Owners are usually told that running PABW blood will lower anesthetic risk by detecting underlying illnesses that would contraindicate surgery and anesthesia and/or require an adjustment to the anesthetic protocol (meaning, a change in the medications that are used for the anesthetic).
A 2008 Study conducted at the University of Leipzig to determine if routine hematological and biochemical screening is of benefit in dogs requiring anesthesia found that, if no potential problems are identified in the patient’s history or physical exam, PABW is unlikely to yield additional information and did not prompt major changes to anesthetic technique.Dr. Nancy Brock, DVM, Board Certified Veterinary Anesthesiologist
When it comes to medical screening tests, tests are only useful if they are applied to an at risk population and the information the test provides is actionable and relevant; the doctors at the Renforth Vet Clinic do not believe that PABW for young and healthy patients meet this criteria.
A study conducted at the University of Leipzig to determine if routine hematological and biochemical screening is of benefit in dogs requiring anesthesia found that, if no potential problems are identified in the patient’s history or physical exam, PABW is unlikely to yield additional information and did not prompt major changes to anesthetic technique.
What owners are often NOT told about pre-anesthetic blood screening:
1. PABW will not indicate whether or not your pet will have an adverse reaction to an anesthetic drug. The only way to know if an animal (or human being for that matter) will have an adverse reaction to an anesthetic medication is to administer the medication. Fortunately these reactions are exceptionally rare. The risk of some kind of anesthetic complication is generally cited as 1 in 100,000 patients. The definition of “complication” ranges from minor reactions like a small swelling at the site of an injection to more serious reactions, even anaphylaxis and death. The truth is that your pet is at more risk on a drive together to the grocery store than he or she is to have an adverse reaction to an anesthetic drug.
2. The argument that PABW is routinely done in all human patients is, put quite simply, false. Unless human patients have an identified illness that could impact the outcome of a procedure, human doctors are unlikely to request PABW. To quote findings from a 2011 study investigating the value of pre-operative blood work in human medicine: “During the past few decades this practice has been a subject of close scrutiny due to low yield and high aggregate cost. Performing routine screening tests in patients who are otherwise healthy is invariably of little value in detecting disease and in changing the anesthetic management or outcome.
3. In some cases, these tests provide results that are, in effect, false positives that prompt further testing that is expensive, both in terms of financial cost to owners and stress to their pet. According to the abstract of the article referenced above “A large number of investigations which are costly to pursue often detect abnormalities of no clinical relevance, may be risky to patients and cause unnecessary delay or cancellation of surgery.”