Quantitative scale for measuring serum lipemia using optical transmittance measurements

Carrying out an adequate classification of elevated content of lipoproteins in the blood is of great importance in the clinical and research field. High lipoprotein levels can mask pathologies in the blood and affect the interpretation of blood results. In this study, we propose an unambiguous quantitative scale for lipemia based on optical transmittance measurements at two specific wavelengths of whole blood samples. Whole blood drawn from donors (105 in total) aged between 18 and 65 years, divided into two groups, was tested after a fasting period of 8–10 h. Trained technicians visually determined the degree of lipemia. Lipid profile analysis of the first group (48 samples) and transmittance measurements of the plasma (57 samples) of the second group were obtained. We found that the correspondence between the concentration of any of the analyzed lipoproteins and the degree of lipemia, determined visually, is not one-to-one for most of the samples. A simple theoretical analysis based on Mie scattering is presented to elucidate the possible contribution of different lipoproteins to the observed degree of lipemia in the different blood samples. Our analysis suggests that the turbidity of blood serum is due only to VLDL lipoproteins and is directly related to their size. The reclassification of the degree of lipemia using our proposed quantitative scale coincides with the original classification performed visually by the trained technician in 65 % of the cases.