A Blood Hematocrit Test Strip

This paper reports a self-propelled microfluidic hematocrit (HCT) test that uses the correlation between blood hematocrit and wicking distance of blood in a special paper matrix. The enabling feature is a novel blood volume metering method that allows sampling from the fingertip and reliably generates a highly precise blood volume of 47.7 ±1.9 μ1 (CV 4%) that is transferred into a porous paper matrix. A dissolvable valve ensures a relaxed time window for blood sampling, making it highly user-friendly and resilient to overfilling. The presented hematocrit test strip poses a simple, cheap, equipment-free solution for patient-centric hematocrit measurements.