A sniffer (detecting) dog is conventionally defined as an animal trained to use its
olfactory perceptions for detecting a vast array of substances, mostly volatile organic
compounds (VOCs), including those exceptionally or exclusively generated in humans
bearing specific pathologies. Such an extraordinary sniffing performance translates into
the capability of detecting compounds close to the femtomolar level, with performance
comparable to that of current mass spectrometry-based laboratory applications. Not only
can dogs accurately detect “abnormal volatilomes” reflecting something wrong
happening to their owners, but they can also perceive visual, vocal and behavioral
signals, which altogether would contribute to raise their alertness. Although it seems
reasonable to conclude that sniffer dogs could never be considered absolutely
“diagnostic” for a given disorder, several lines of evidence attest that they may serve as
efficient screening aids for many pathological conditions affecting their human
companions. Favorable results have been obtained in trials on cancers, diabetes,
seizures, narcolepsy and migraine, whilst interesting evidence is also emerging on the
capability of early and accurately identify patients with infectious diseases. This would
lead the way to prosing an “olfactory fingerprint” loop, where evidence that dogs can
identify the presence of human pathologies provides implicit proof of the existence of
disease-specific volatilomes, which can be studied for developing laboratory techniques.
Contextually, the evidence that specific pathologies are associated with abnormal VOCs
generation may serve as reliable basis for training dogs to detect these compounds, even
(or especially) in patients at an asymptomatic phase.
This paper was accepted for publication in the journal Clinical Chemistry and Laboratory Medicine and the definitive published version is available at https://doi.org/10.1515/cclm-2019-1269.