Pre-anaesthetic Blood Testing

PA Blood Tests: Are they necessary?

Pre anaesthetic blood screening is a fast growing trend in veterinary practice. There are a number of reason blood tests are run:

Patient safety: This is the prime reason practices advocate PA blood tests to their clients.

Remove the guess factor: Even with thorough patient evaluation, there will always be the odd animal with a significant condition (even though they look normal) that will react adversely to the effects of anaesthesia (during, or at some point following recovery).

Revenue: when we remove the altruistic merits of running blood tests, at its core, lab work is a solid means of revenue generation. This is particularly so with in-house laboratory systems.

Protection against litigation: This is an unfortunate side of society. If you get it wrong, or you fail to cover all bases, you place yourself at risk of litigation.

There is one more advantage, particularly in young patients, and that is the establishment of a patient blood profile.  This can be used as a base point to compare back to, particularly as the animal ages.


Is PA Blood screening effective?

In a study performed at the University of Leipzig,  1537 dogs were evaluated by physical examination then blood tests.  84.1% were classified as healthy and able to receive an anaesthetic. A small percentage (8%) of these dogs (evaluated by physical examination as normal) were found to have abnormal lab results that would have changed their ASA risk rating. Only 0.8% of evaluated dogs would have had their anaesthetic procedure postponed based on lab results.

Just how these results are interpreted will depend which side of the fence you stand. From the owners perspective, physical examination alone will identify the majority of animals fit to receive an anaesthetic. From the clinicians perspective, there are some ‘sleeping dogs’ here just waiting for an opportunity to create havoc on your watch. Who is right or wrong will depend who declined the blood test on the ‘sleeping dog’? Was it the owner for financial reasons, or the vet because they backed the odds of something going wrong being in their favour? Either way, it was the patient that ultimately suffered.

Blood test results may not change whether a patient receives an anaesthetic, but they may change the type of protocol used (medications as well as the provision of fluids), and the care the patient receives to minimise the impact anaesthesia & surgery have on their abnormality.

Older patients are much easier to advocate PA laboratory tests for. The chance of some form of organ dysfunction or haematology abnormality in this group is much higher. The tricky group are definitely the ‘babies & teenagers’.



Veterinary Anesthesia and Analgesia (Excerpt from Google)

Why I hate pre-anaesthetic blood tests in our pets!:  Dr Liz. A tongue in cheek article

Preanaesthetic Testing: IDEXX

Do tests first: Pre-surgical blood work may eliminate variety of surprises: DVM 360

Is routine pre-anaesthetic haematological and biochemical screening justified in dogs?


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