Quantification of Red and White Blood Cells using Scattering Information Extraction from Vis-NIR Spectrum: Towards Spectroscopy Point-of-Care Hemogram Cell Counts

Red blood cells (RBC) and white blood cells (WBC) counts are an important part of hemogram diagnosis. These are quantified by laboratory flow cytometry analysis with laser scattering or impedance detection. The measurement is also complemented by manual microscopy counts using the Neubauer chamber technique. Scattering of single cells is already used as a standard technology for differentiated cell counts in flow cytometry, but it implies capillary cell separation. This research explores the scattering properties of whole blood to determine correlations with RBC and WBC counts. Scattering information in blood samples can be categorized as i. geometrical scattering where non-absorbed light is scattered by reflection; ii. Mie scattering - where light is scattered by particles of similar size of the wavelength; and iii. Rayleigh scattering - where light is scattered by particles smaller than the wavelength of incident light. Herein, we explore the scattering correction coefficients of visible - near-infrared (Vis-NIR) of 320-850 nm dog blood absorption spectra to derive direct correlations to RBC and WBC counts using multivariate linear regression (MLR). Results show the feasibility of categorical and classification of the scattering properties of dog blood, allowing the discrimination of high and low values of both RBC and WBC, as well as, their categorical quantification: i. RBC with a correlation of 0.5739 and a standard error of 1.33 log10(cells/L); and ii. WBC with a correlation of 0.5900 and a standard error of 7.70 log10(cells/L) when compared to cell cytometry impedance counts.