Red blood cell sedimentation rate measurements in a high aspect ratio microchannel

BACKGROUND: The erythrocyte sedimentation rate (ESR) test is commonly used in clinical practice for monitoring, screening and diagnosing pathological conditions and diseases related to the inflammatory response of the immune system. Several ESR techniques have been developed over the years improving the reliability, the precision and the duration of the measurement. OBJECTIVE: In the present study a new low cost micro-ESR technique is described providing the major advantage of reducing the measurement time and the blood sample volume by multiple times compared to the commercial methods. METHODS: Blood samples were obtained from healthy donors within the age group of 24–28 years and the haematocrit was adjusted to 30%, 40% and 50%. The ESR of the samples was measured utilizing a surface tension driven (STD) microfluidic chip and a monitoring device. RESULTS: The evaluation of the method showed a high correlation (0.94, p < 10(–5)) at all haematocrit levels with the commercial instrument indicating the feasibility of the technique. CONCLUSIONS: This micro-ESR technique provides the potential for a simple, low cost and fast tool for ESR measurement using low blood volume acquired by finger prick.