Use of Dual-Force Aggregation as a Multiplexed, Rapid Point-of-Care Screening Method for White Blood Cell Counting...

Enumeration of blood cells is an integral metric for evaluating patient health and can be used to screen for a wide range of diseases and conditions. Conventional methods rely on large, expensive, and complicated instrumentation that requires trained technicians and is not amenable to point-of-care analysis. This work demonstrates the use of a multiplexed, bead-based assay for both rapid white blood cell (WBC) count screening and accurate, multiplexed WBC counts for point-of-care analysis.

Blood samples were lysed and diluted before being incubated with silica-coated magnetic particles under chaotropic conditions, a rotating magnetic field, and a source of agitation. The resulting bead aggregation was imaged and correlated to a known WBC count. After establishing standard curves, the WBC count for 18 whole blood samples were determined by this method and compared to values obtained conventionally.

When the optimal dilution factor for lysis of whole blood samples was established, 17 of 18 samples (94.4%) were correctly screened and categorized as having high, typical, or low WBC count, while 14 of 18 samples were within 16% of the reported clinical values. The developed system provides analysis of 13 samples in <3 min with a total analysis time of approximately 10 min (including incubation and dilution) and represents comparable throughput to conventional instrumentation, while providing point-of-care capability with reduced size (14 × 21 × 14 cm) and simplicity.

This work demonstrates the potential for a multiplexed, bead-based assay to be used as a rapid, point-of-care screening method for WBC counting from whole blood samples.