Clinical Application of Volatile Organic Compound–Based Exhaled Breath Tests for Cancer Diagnosis—In Reply

In Reply The letter by Cao et al viewed our review¹ as an analysis of individual volatile organic compounds (VOCs) rather than of breath tests based on identifiable VOCs. Although we excluded studies that involved sensors and pattern recognition techniques that did not report the identity of the VOCs, our analysis was based on the entire breath test, not individual VOCs. This is the reason for the letter’s various assumptions and interpretations that we did not intend to examine or claim.