Development of a low cost precision blood resistivity measurement device based on Thompson Lampard theorem

Certain diseases detection on the hematocrit level in the human blood can be identified based on resistivity or its impedance. Currently, physicians depend on different laboratory tests of blood for diagnosing and monitoring diseases. Testing blood sample is easier than obtaining a tissue sample from a specific organ and hence makes it a better option for diagnosis. A design system measuring the blood sample is needed to solve this problem. Conventional measurement methods, using automated analyzers, are quite high in cost for its operation and maintenance. This paper proposes a low cost system of human blood resistivity measurement. Resistivity of the blood sample is measured using extended Thompson Lampard theorem. This theorem is based on the cross conductance measurement and is used to measure the resistivity of the materials. The proposed measurement system consists of newly designed cylindrical test cell to measure the resistivity of the blood with good order of accuracy. The blood samples are taken from the patients who have been diagnosed of certain diseases. Results show that the designed test cell provides good performance on resistivity measurement and also it is found that the resistivity of human blood varies from 80 Ω-cm to 260 Ω-cm when measured at frequencies of 1kHz, 10kHz and 20kHz. It is verify there is ample scope of resistivity measurement in the diagnosis of certain diseases.