Noninvasive disease detection through odor compounds is expanding across breath, urine, and sebum to diagnose conditions ranging from Parkinson’s disease to cancers and infections.

Nurses in a Norwegian cancer ward have reported relying on their sense of smell to flag issues like urine infections, digestive bleeding, and cell necrosis, illustrating real-world diagnostic potential of odors.

Breath- and scent-based diagnostics are being explored, with historical and modern notes on odor-driven detection guiding current work.

Key challenges include standardizing breath sample collection, controlling contaminants, accounting for variability in breath profiles, and translating promising findings into reliable, market-ready tests.

Technologies such as gas chromatography-mass spectrometry and portable electronic noses are used to pursue rapid diagnostics and fewer false positives.

Advances in VOC technology and machine learning are moving odor-based diagnostics closer to clinical use, though adoption awaits resolution of remaining hurdles.

Future applications may distinguish viral from bacterial infections via breath and monitor critically ill patients for sepsis or SIRS in the ICU, with broader deployment contingent on standardization and funding.

Case examples highlight both promise and challenges, underscoring the need for objective, validated odor signatures rather than subjective impressions.

Breath tests detect VOCs using GC-MS and electronic noses, with examples like Helicobacter pylori and potential lung cancer markers; long-term goals include home or clinic use.

Current practical tools include gastric H. pylori breath tests and efforts to develop at-home or clinic-based VOC analyses in breath, urine, or sebum.

Progress is shifting from theory to real-world application as researchers seek reliable odor-based biomarkers for diagnosis.

Notable developments include TOBY, a urine-based bladder cancer test using AI to analyze VOCs that has FDA Breakthrough Device designation in 2026 and is nearing commercial launch; parallel efforts target Alzheimer’s disease.