Near Infrared Analysis of Dried Human Serum for Determining Human Serum Urea Concentration

Abstract

We determined the human serum urea concentration from the near infrared spectrum of dried sera to assess whether the removal of water could provide an improvement over the direct analysis of unmodified samples. The results ( r = 0.989, SEP = 1.0 mmol L⁻¹) obtained by the analysis of dried sera by using multiple linear least-squares regression were comparable to the results ( r = 0.993, SEP = 0.8 mmol L⁻¹) obtained by the analysis of unmodified serum by using Partial Least-Squares regression.¹ While the NIR determination of serum urea concentration in dried specimens simplifies the regression analysis it requires more technical competence and is more time-consuming.