A new meaning for lab reports

Dogs are the most sensitive investigated to date with a sense of smell that is 10 000 to 100 000 times more sensitive than ours, meaning that they can identify chemical traces in the range of parts per trillion.

For many years this phenomenal power has been put to use in police and narcotics tracker dogs. Towards the end of the 1980s another role for dogs emerged. The story of a dog alerting its female owner to an early malignant melanoma so impressed the dermatologists treating her that they wrote a letter to the Lancet. They described how the dog kept sniffing the skin lesion and on one occasion tried to bite it. It was the dog's behaviour that inspired the patient to visit her doctor, who then identified it as a malignant melanoma. ‘The dog may have saved her life’, concluded the dermatologists.

Following this, researchers successfully trained dogs to identify cancer patients from sniffing breath, skin and stools. Several dog breeds have been used in this simple reward training including Belgian Malinois Shepherd, Labradors and Spaniels. They have detected cancers in breast, gut, ovary, lung, prostate and bladder with an accuracy that usually equals that of clinical diagnostic tools.