Can blood tests detect cancer in dogs?

The short answer

Some specialised blood tests can find molecular signals associated with cancer. That does not mean every blood test detects cancer, or that one result can confirm or rule it out. Your veterinarian interprets tests alongside your dog’s symptoms, examination and other findings.

Routine bloodwork and liquid biopsy answer different questions

Routine bloodwork can help a veterinarian assess your dog’s overall condition and plan further investigation. Establishing a cancer diagnosis may require examination of cells or tissue; imaging can help assess where disease is present. The appropriate tests depend on the suspected cancer. AAHA: Tumor diagnostics and staging.

A liquid biopsy examines material circulating in blood, such as cell-free DNA. Researchers can look for patterns linked to cancer. In the CANDiD study, a specific liquid-biopsy test was evaluated in an independent testing set. Detection varied by cancer type and stage. Results from that assay do not establish the performance of a different test. CANDiD study, PLOS ONE, 2022.

Three questions to ask before choosing a test

• Is it intended for screening a healthy dog, investigating suspected cancer, or monitoring a diagnosed cancer?
• What evidence supports that particular use, and what can the test miss?
• What would we do after either a positive or a negative result?

These questions help connect testing to a useful next step in your dog’s care.

Where Canos fits

Canos Origin provides genetic health information and an epigenetic baseline. It does not screen for, diagnose or rule out cancer. Canos OncoTrack is an exploratory monitoring trial for dogs already diagnosed with cancer. Participation is subject to team review and does not replace veterinary care.

If your dog has a new or persistent health concern, contact your veterinarian rather than relying on a screening result.