Concentration measurements of multiple analytes in human sera by near-infrared laser Raman spectroscopy.

Our primary goal in this study is to demonstrate that near-infrared Raman spectroscopy is feasible as a rapid and reagentless analytic method for clinical diagnostics. Raman spectra were collected on human sera by use of a 785-nm excitation laser and a single-stage holographic spectrometer. A partial-least-squares method was used to predict the analyte concentrations of interest. The prediction errors of total protein, albumin, triglyceride, and glucose in human sera ranged from 1.0% to 10%, which are highly acceptable for clinical diagnosis, of their mean physiological levels. For investigating the potential application of near-infrared Raman spectroscopy in screening of therapeutical drugs and substances of abuse the concentrations of acetaminophen, ethanol, and codeine in water solution were measured in the same fashion. The errors of the Raman tests for acetaminophen and ethanol are lower than their toxic levels in human serum, and the sensitivity for detection of codeine fails to reach its toxic level.