Inflammatory processes in the lung can or will elicit oxidative stress. The degree of oxidative stress can be determined by measuring hydrogen peroxide (H(2)O(2)) concentration in exhaled breath condensate (EBC) but the methods to measure H(2)O(2) are all rather time consuming and only reliable and/or accurate in the hand of skilled technicians in a dedicated laboratory. We tested a new commercial device (Ecocheck), developed to offer a less time-consuming method to measure H(2)O(2). We validated this new method according the NCCLS EP10-A2 protocol. The validation shows that the imprecision in the low range is high (28.4%) and declines with higher concentrations of H(2)O(2) (up to 6.6%). The Ecocheck is "an easy to use" measuring device for routine measurements getting quick results without the need for skilled technicians to determine H(2)O(2) concentrations.