Just like their human owners, many dogs suffer from cancer, which is often malignant, spreading through the body via blood. Once tumors have spread, they usually result in a poor outcome, including death. The tumor cells in circulation (CTCs) can be counted in the blood of people with cancer using immunocapture devices. The number of CTCs in blood can tell the clinician how aggressive the tumor is, its potential to spread, and how long a patient might survive. There is currently no such way of detecting CTCs in our canine companions. Development of an assay for counting CTCs in canine blood would be of tremendous benefit to our canine patients because, from a simple blood test, we could detect hidden tumors and gather information on tumor severity and the likelihood of spread or metastasis. The investigators will test a novel immunocapture microdevice - the GEDI - for counting tumor cells in canine blood. This device can capture CTCs from blood in human patients with various cancers. This study will test its potential to do the same for dogs. In this pilot study, blood samples from healthy dogs will be manipulated to test the ability to count how many added tumor cells are captured by the GEDI device. If the GEDI does capture the tumor cells, the next step will be to determine if the device can capture CTCs from the blood of dogs that are known to have cancer, paving a path to early detection of cancer in dogs.