Pre-op Bloodwork for My Dog or Cat?

We talk to a lot of pet owners who wonder, “Does my pet really need pre-op bloodwork?”

That’s a great question and one that is difficult to answer because there are a lot of opinions and not enough facts. But before you click away, I think there is enough scientific evidence to help you decide if it is needed for your pet.

The following link to a scientific study of 1537 dogs at a German University Veterinary Hospital sought to determine the value of pre-op bloodwork:

If scientific studies make your head spin, the CONCLUSION and CLINICAL RELEVANCE sections are pasted below.

“Conclusion  The changes revealed by pre-operative screening were usually of little clinical relevance and did not prompt major changes to the anaesthetic technique.”

“Clinical relevance  In dogs, pre-anaesthetic laboratory examination is unlikely to yield additional important information if no potential problems are identified in the history and on physical examination.”

This seems to be a polarizing subject in veterinary medicine, and there are plenty of experts and real life cases supporting both sides. All would agree, it is never wrong to perform pre-op bloodwork. The dilemma occurs when you are the one paying for it. According to this study, most of the time for apparently healthy patients, all values are normal, and anesthesia and surgery proceed with no change. This makes it hard for the person paying for it to justify pre-op bloodwork.


At SpayXperts, Spay Neuter Specialty Clinic, we have performed thousands of spay neuter surgeries using the patient’s medical history and pre-op physical examination (no pre-op bloodwork) to guide our anesthesia and surgery efforts. Our results are consistent with this study. The patients that incur complications usually have cardiovascular or respiratory problems which are not revealed on CBC or serum chemistry results. Fatality rates can be <0.05% with Xpert care.

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