Veterinarians frequently recommend doing lab work, especially in an aging patient, to detect early signs of illness like renal or liver disease, diabetes or other hormone-related problems. Then comes the inevitable question: “ Doctor, will this blood test tell you if my pet has cancer?” And the answer to that question is always “ unfortunately no”.

The idea of a blood test for cancer seemed too good to be true until recent advances in DNA sequencing technology have allowed to turn this dream into a promising reality.

This may allow your veterinarian to detect certain cancers in their earlier stages, allowing for earlier treatment and better outcomes.  Liquid biopsy testing, as it is referred to, can become another tool in your veterinarian’s arsenal to better diagnose and treat cancer in your dog. But like any test it comes with its own set of limitations and by itself it does not diagnose cancer. A positive result increases the likelihood that a pet has cancer but does not confirm it.

The detection rate is higher for certain types of cancer than others, and a positive result should never be the only mode of diagnosis. However, it may allow your veterinarian to have a higher degree of suspicion for cancer, and recommend further testing like x-rays, ultrasound and advanced imaging like MRI. 

So far, this test has been shown to detect 30 distinct types of cancer, although with variable detection rates depending on the type of cancer present according to a study published in JAVMA in June 2023 ( Clinical experience with next-generation sequencing-based liquid biopsy testing for cancer detection in dogs: a review of 1,500 consecutive clinical cases : Allison L. O’Kell DVM, MS, DACVIM, Katherine M.)

So next time you ask your veterinarian the question: “Doctor, will this blood test tell you if my pet has cancer?” The answer might be “yes, it will”.

Dr. Caroline Simard

Medical Director and Co-Founder

Pets After Dark