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 countingmethod based onthe 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.