Breathomics and clinical chemistry: diagnostic applications of volatile organic compounds

Abstract

Volatile organic compounds (VOCs) are small carbon-based chemicals found in the breath that can reflect changes in the body's metabolism. These compounds are either produced inside the body or absorbed from the environment, and their levels can change in response to diseases. Because breath collection is simple, safe, and painless, VOCs are now being studied as useful tools for diagnosing and monitoring a wide range of health conditions. This review explains how VOCs are produced in the body through processes such as fat breakdown, cholesterol production, and responses to stress or infection. It also discusses how factors such as diet, medications, and gut bacteria can affect the types and amounts of VOCs in the breath of humans. Different technologies, such as gas chromatography–mass spectrometry, selected ion flow tube mass spectrometry, and electronic noses (eNoses), are used to detect and analyze these compounds. Moreover, breath VOCs have been linked to diseases such as diabetes, asthma, lung cancer, liver diseases, kidney diseases, and neurological conditions. However, challenges remain, including standardizing breath tests and confirming results in large studies. With further development, breath analysis could become a fast, accurate, and noninvasive way to diagnose diseases and track treatment progress.