As a veterinarian, I get asked numerous times a day by pet parents and staff about lab work. Questions range from: Why does my pet need this type of lab work? To, how do you interpret these numbers into English?
Blood work may be performed for a variety of reasons. Veterinarians utilize different laboratories when trying to ensure accurate results in a timely manner. We are able to do in-house lab work and/or send-out specimens to outside reference laboratories. The most important thing is that the laboratory is credible, because not all laboratories, unfortunately, are capable of achieving accurate and timely results.
Every veterinarian tackles cases differently. But most of us, before we jump to blood work and other diagnostics, use our experience and clinical skills to gather information. We collect history and perform a physical examination that includes all our senses (with the exception of taste).
Only after we have trusted our experience and performed a physical examination, do we go to diagnostics to get further answers. Sometimes we find ourselves needing to see numbers, values, images and scans, because the initial exam did not lead to a definitive diagnosis.
While our clinical senses are important, they are not able to show us liver, kidney and pancreas functions, for example.
A pet parent who takes his sick pet to the veterinarian is usually expecting some sort of diagnosis or a reason why his pet “ain’t doing right” or what we, in the clinic, abbreviate as ADR.
When we recommend getting blood work or images, we do that to either confirm or rule out our hypotheses (or hunches) that we have gathered from our patient history (that the pet parent provides) and the physical examination.
To be honest, I find it a bit unfair sometimes, when physicians (human) do not get questioned from their patients about blood work (even if it’s not urgently needed) while we veterinarians have to constantly defend and express why we strongly recommend blood work, especially since our patients are not able to vocalize their troubles.
Your veterinarian may also require blood work before anesthesia. As far as anesthesia is concerned, there isn’t a “one plan fits all patients.”
Pre-anesthetic blood work is necessary to ensure normal organ functions prior to administration of anesthesia. Medications including sedation drugs, intravenous injections to induce anesthesia or gas anesthesia to maintain anesthesia are mainly metabolized in the liver and kidneys. The choice of medications can differ from one patient to another based on numbers.
Veterinarians may even choose not to do the surgery that day or ever, based on the lab work results, and they may choose a completely different plan of action that’s best for the patient.
Another reason for doing blood work is for monitoring certain drug levels. This helps in deciding whether we need to change the dose of a certain medication, or change it completely to another medication if it’s reaching a toxic level in the blood. This is especially important for patients on a seizure medication such as phenobarbital or bromide, or a thyroid medication such as levothyroxine.
Blood work is also important in managing and monitoring the progress of treatment. We would never know if a treatment plan is moving in the right direction if we don’t compare pre- and post-treatment numbers. Just as your physician may need to test your cholesterol levels prior to placing you on a statin medication and again after taking the medication, so does your veterinarian need to test your pet who may suffer from kidney, liver, heart or thyroid disease – all of which require long-term management and repetitive testing.
If blood work isn’t performed, it ends up being a guessing game that could compromise your pet’s health.
In addition, your veterinarian may recommend blood work for your pet to get baseline numbers for future blood results.
Most of us know that pets mature and age at faster rates than do humans. As a guideline, 15 human years is equivalent to the first year of a medium-size dog’s life. Year two for a dog equals nine years for a human.
And after that, each human year equals approximately five years for a dog.
The American Veterinary Medical Association considers cats and dogs seven years of age or older to be senior patients.
Would you be OK if your physician recommended blood work every five years? Don’t you believe that many things could happen in five years and conditions can be easily missed?
For this reason, we repeat blood work every six months to a year, so that we can catch any abnormalities before they become troublesome to our patients.
Finally, I am a firm believer that routine blood work is a useful tool that allows veterinarians to discover abnormalities and potential health risks that can easily be missed during an office visit.