A rugged, miniature, spectroscopic 
gas analyzer apparatus for rapid, non-invasive, multi-component breath monitoring and analysis and subsequent determination of Q or other 
medical diagnostic applications. The 
system is comprised of one or more IR emitters focussed by optical elements through a 
low volume sample 
cell receiving a sample input of a patient's breath for analysis. The patient either at rest or during exercise, inhales C2H2—SF6 mixtures (balance of 
oxygen and 
nitrogen) which is subsequently monitored upon 
exhalation for CO2, H2O, C2H2, and SF6 which can be employed to determine Q directly and accurately. Measurements are performed in real-time or via post-
processing of stored 
original data. Due to its small size, ruggedness, and low 
power consumption, the monitor can conveniently be employed in the field or data can also be retrieved remotely using 
telemetry. The miniature analyzer operates on the principle of 
infrared absorption spectroscopy and allows very precise concentration measurements of the analytes of interest, without any bias or interference from other matrix components.