Raman Spectroscopy for Urea Breath Test

Abstract

The urea breath test is a non-invasive diagnostic method for Helicobacter pylori infections, which relies on the change in the proportion of 13CO2 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 Helicobacter pylori detection via the urea breath test using 13CO2 as a biomarker is affected by measurement errors, including equipment error and δ13C measurement uncertainty. We present a Raman scattering-based gas analyzer capable of δ13C measurements in exhaled air. The technical details of the various measurement conditions have been discussed. Standard gas samples were measured. 12CO2 and 13CO2 calibration coefficients were determined. The Raman spectrum of the exhaled air was measured and the δ13C 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.

Reagentless Vis-NIR Spectroscopy Point-of-Care for Feline Total White Blood Cell Counts

“…Matrix effects are inherent to sample properties, such as pH or scattering effects, affecting the proportions of Mie and Rayleigh scattering and absorbance bands [4,5]. Clinical and analytical chemistry address spectral interference through sample composition simplification (e.g., separation using filtration, centrifugation, chromatography) or reaction specificity on biochips (e.g., immunological reactions, molecularly imprinted polimers, aptamers), not taking advantage of the rich information present in spectra [6][7][8][9][10]. Unscrambling the multi-scaled interference and matrix effects, and unlocking constituent-specific information in each spectrum, lies at the heart of reagentless POC technology [1,11,12].…”