Quantitative FT-IR spectrometry of blood constituents

The evaluation of blood constituents can provide a powerful clinical diagnostic tool. Improvements in technology point to continuous non-invasive measurements and optical techniques seem to be a viable approach. To assess feasibility, albumin, cholesterol, ethanol, glucose, lactic acid and urea were measured in-vitro using Fourier transform infrared (FT-IR) spectroscopy. The peak height and corresponding peak area of the spectra were computed for concentration prediction. This univariate method was compared with partial least squares (PLS) and principal component regression (PCR) multivariate routines. The standard errors of calibration obtained were: albumin (49.1 mg/dl), cholesterol (7.8 mg/dl), ethanol (7,8 mg/dl), glucose (10.2 mg/dl), lactic acid (3.3 mg/dl) and urea (8.4 mg/dl).