A simple and low-cost device performing blood cell counting based on lens-free shadow imaging technique

Abstract

Complete blood count (CBC) is a basic and important diagnostic procedure in pathological laboratories. However, current technologies such as hemocytometry, impedancemetry, or flow-cytometry, are either time-consuming or requiring bulky and high-cost of instrumentation. To address this issue we demonstrate a compact, cost-effective, and automated blood cell counting method based on the lens-free shadow imaging technique. For that a lens-free shadow imaging technique based blood cell counting device was fabricated using a blue light emitting diode (LED) and a complementary metal oxide semiconductor (CMOS) image sensor. The shadow images of the blood cells, i.e., diffraction patterns, were captured by the device and processed automatically using a custom developed algorithm to count and differentiate the cells. The comparative study from 21 outpatient whole blood samples was carried out with the fully automated hematology analyzer (LH 750, Beckman Coulter). The comparison between the lens-free shadow imaging device and the standard reference system showed correlation indices of 0.878 for red blood cell (RBC) and 0.927 for white blood cell (WBC). The linearity comparison gave a statistical trend of y=0.9432x with R2=0.99 for RBC and y=0.7395x with R2=0.92 for WBC. Also the correlation coefficient for WBC subpopulations, i.e., neutrophil, lymphocyte, and monocyte, for each individual sample was >0.90. This cost-effective and compact blood cell counting system can be utilized as a powerful point of care (POC) tool, which could play an important role in primary healthcare, especially in areas with limited resources. Since the system is capable to send the images wirelessly and process them on a moderate smart phone, therefore, the proposed system possesses great potential in telemedicine applications.