A wave of noninvasive diagnostic work is advancing from odor compounds in breath, urine, and sebum toward detecting diseases such as Alzheimer’s, Parkinson’s, and various cancers by analyzing volatile molecules.

Nurses in a Norwegian cancer ward have relied on their sense of smell to identify conditions like urine infections, digestive bleeding, and cell necrosis, underscoring the potential diagnostic value of odors.

Experts cite the need to standardize breath and sebum collection, control for environmental and contaminant factors, and validate biomarkers across larger populations to translate promising findings into reliable tests.

Broader challenges include harmonizing tests across studies and accounting for how environment shapes breath and sebum profiles, as biomarkers move toward clinical validation.

Case examples show both promise and hurdles, highlighting the importance of objective, validated odor signatures over subjective impressions.

Advances in VOC technology and machine learning are bringing odor-based diagnostics closer to clinical use, though deployment awaits overcoming remaining obstacles.

Future applications include using breath to distinguish viral from bacterial infections and monitoring ICU patients for sepsis or systemic inflammatory responses, pending standardization and funding.

Efforts to separate viral from bacterial infection signals in breath could guide antibiotic use and improve critical care monitoring for sepsis-related conditions.

Techniques such as gas chromatography–mass spectrometry and portable electronic noses are being used to identify disease-related VOCs for rapid diagnostics and reduced false positives.

The field is moving from theory to real-world use as researchers seek reliable odor-based biomarkers for medical diagnosis.

A real-world development is TOBY, a urine-based bladder cancer test that uses AI to analyze VOC patterns and has FDA Breakthrough Device designation, signaling progress toward commercialization; parallel work targets Alzheimer’s disease.

TOBY’s AI-driven urine test for bladder cancer is nearing commercial approval, reflecting a tangible step in odor-based diagnostics.