Behind the scenes, scent detection dogs have also been able to accurately detect infection, including C. difficile (a bacterial infection often acquired in healthcare settings) and malaria, in both human patients and biological samples. They can also identify many types of cancer, including (but likely not limited to) skin, lung, breast, and bladder cancers. For example, one study tested dogs for the detection of both lung and breast cancer in breath samples collected from patients. Following a 2-3 week training program, the five dogs were able to distinguish positive lung cancer samples from negative samples 99% of the time, and positive breast cancer samples from negative samples 88-98% of the time. Interestingly, each of the dogs included in this study were household dogs with only a basic obedience class and the drive to work in their toolkit. As this example illustrates, trained animals have similar–or in some cases, higher–success rates than medical devices and laboratory procedures.

Dogs can work through many samples quickly, at a low cost, with minimal or no interaction with patients. For example, healthcare workers can collect breath, sweat, urine, or blood samples for dogs to process, rather than having the dog examine patients directly. This allows the dogs to work with minimal environmental distraction, and bypasses the necessity to work directly with patients who may be uncomfortable around dogs. Despite these advantages, the chances are low that your routine blood draw or breast biopsy is being examined by a dog in the laboratory. For now, the only dogs you’ll meet in the hospital hallway are mood-boosting therapy dogs, and service dogs aiding their handlers (also both worthy canine causes).