A Miniaturized Device for Blood Typing Using a Simplified Spectrophotometric Approach

Abstract

A new blood typing technology has been developed by Narayanan et al. using ultraviolet and visible light spectroscopy. Blood groups can be typed using changes in the UV and visible spectra between antibody treated and non-treated samples. These changes can be observed by optical density measurements in the 665 to 1000 nm region. Comparison of the slopes between the optical densities of control samples and antibody treated samples can be used to calculate an agglutination index number (A.I.) that describes whether or not the sample reacts to the antibody treatment.

A simplified system using a discrete LED/photodiode system to take the place of the monochromator⁄photodiode array system in the spectrophotometer has been developed by Anthony and Ramasubramanian that has shown promising results reproducing the measurements of the spectrophotometer. This system was used as a starting point for the proposed research.

The purpose of this research is to evaluate the scattering⁄absorption effects of red blood cells, designing a miniaturized system, and investigate this approach. The miniaturized system has been able to reproduce similar results to the spectrophotometer and is consistent with the simplified method of Anthony and Ramasubramanian. The miniaturized system also explores the use of fiber optics to improve repeatability of source mounting. A plano-convex lens is used to collimate the source beam incident on the detector and eliminate the need for specific placement of the sample that would be necessary for the converging/diverging beam used previously. This allows the components to be placed closer together and further miniaturize the setup.

Packaging of this system into a compact device has been investigated and a device configuration is proposed. This packaged device could be modified further to include fluid handling that would yield a fully automated system.

It is concluded that an automated blood typing system or a possible bedside pretransfusion safety device using the spectrophotometric approach is a possibility.