Clinical application of volatile organic compound analysis for detecting infectious diseases

Abstract

This review article introduces the significance of testing of volatile organic compounds (VOCs) in clinical samples and summarizes important features of some of the technologies. Compared to other human diseases such as cancer, studies on VOC analysis in cases of infectious diseases are limited. Here, we have described results of studies which have used some of the appropriate technologies to evaluate VOC biomarkers and biomarker profiles associated with infections. The publications reviewed include important infections of the respiratory tract, gastrointestinal tract, urinary tract, and nasal cavity. The results highlight the use of VOC biomarker profiles resulting from certain infectious diseases in discriminating between infected and healthy subjects. Infection-related VOC profiles measured in exhaled breath as well as from headspaces of feces or urine samples are a source of information with respect to disease detection. The volatiles emitted in clinical matrices may on the one hand represent metabolites of the infecting pathogen or on the other hand reflect pathogen-induced host responses or, indeed, a combination of both. Because exhaled-breath samples are easy to collect and online instruments are commercially available, VOC analysis in exhaled breath appears to be a promising tool for noninvasive detection and monitoring of infectious diseases.

Fig 1

Flow chart showing a typical study design. PLS-DA, partial least-squares model for discriminant analysis; MESI, membrane extraction with sorbent interface; SPME, solid-phase microextraction; NIST, National Institute of Standards and Technology; PCA, principal component analysis; Neg, negative; Pos, positive; VOCs, volatile organic compounds; GC-MS, gas chromatography-mass spectrometry.