Raman Spectroscopy for Urea Breath Test.

The urea breath test is a non-invasive diagnostic method for infections, which relies on the change in the proportion of CO in exhaled air. Nondispersive infrared sensors are commonly used for the urea breath test in laboratory equipment, but Raman spectroscopy demonstrated potential for more accurate measurements. The accuracy of the detection via the urea breath test using CO as a biomarker is affected by measurement errors, including equipment error and δC measurement uncertainty. We present a Raman scattering-based gas analyzer capable of δC measurements in exhaled air. The technical details of the various measurement conditions have been discussed. Standard gas samples were measured. CO and CO calibration coefficients were determined. The Raman spectrum of the exhaled air was measured and the δC change (in the process of the urea breath test) was calculated. The total error measured was 6% and does not exceed the limit of 10% that was analytically calculated.