Visible/Near-Infrared Spectrophotometric Blood Typing Sensor for Automated Near-Patient Testing

Automation in near-patient ABO testing has been prohibitive due to cost. Recently, a spectrophotometric approach to blood typing has been developed by examining the spectral slopes of RBC suspensions in saline, in the presence and absence of various antibodies. In this paper, we present a simplified method and a sensor that can replace the spectral imaging component of the diode-array spectrophotometer with a discrete array of LED/IRED and photodiode pairs within the 660 nm-1000 nm wavelength range of interest. An experimental sensor has been designed and evaluated for the reproduction of results recorded on an HP8453 diode-array spectrophotometer. The LED and photodiode pairs are found to successfully reproduce the spectroscopic determination of red blood cell agglutination, as supported by Mie scattering theory examined herein