Method for detecting gaseous component levels in a breath, comprising: receiving a breath through a breath channel, wherein the breath channel is in fluid communication with a flow rate sensor and an electrochemical fuel cell gas sensor measuring a flow rate of the breath received through the breath channel measuring a first time, wherein the first time corresponds to an amount of time elapsed while receiving the breath in the breath channel and calculating a current gaseous component level utilizing the flow rate, first time and an output from the gas sensor. Methods for detecting an error condition while measuring gaseous component levels in a breath comprising: determining if the peak output occurs while breath is still being received in the breath channel and if the peak output occurs while breath is still being received in the breath channel, alerting a user of an error condition.
