Reagent-free hemoglobin estimation on a spinning disc

Abstract

Quantitative estimation of hemoglobin concentration is a commonly required clinical test to assess various manifestations of pathological conditions in blood. While several invasive and non-invasive approaches have been introduced for rapid low-cost determination of hemoglobin levels in patients, these methods have been reported to suffer from various constraints, limiting their applicability for precise quantitative analysis. Methods reporting high levels of quantitative accuracy, on the other hand, are severely challenged for their deployment in resource-limited settings, as these necessitate specialized reagents that demand exclusive storage and transportation facilities as well as trained human resources for deployment in the field. Circumventing these constraints, here we demonstrate a low cost (<$0.01 each test) reagent-free method for hemoglobin estimation on a simple portable unit that can be implemented in under-served locations without sacrificing the fundamental principle of direct evaluation of hemoglobin extracted from the human blood sample. Exploring the fundamental principle of osmotic hemolysis for extraction of hemoglobin from red blood cells, the method harnesses the dynamics of a blood drop on a rotating platform and simple imaging to come up with results in a turn-around time of about 13 min. The efficacy of the device has been justified by validating with established pathological gold standards. These results are likely to pave the pathway of establishing the paradigm of a first-principle based reagent-free evaluation of blood pathology in health and disease.