Measuring haemoglobin with microfluidics and a microscope

Researchers from SigTuple Technologies and the Indian Institute of Science have created an AI-powered, imaging-based tool to estimate haemoglobin levels in the blood — an important biochemical parameter that can indicate a host of medical conditions including anaemia, polycythemia and pulmonary fibrosis. The set-up includes a microfluidic chip and an AI-powered automated microscope that was designed for deriving the total as well as differential counts of blood cells. It has been described in the journal AIP Advances.

Often, medical diagnostics equipment capable of multiparameter assessment, such as haematology analysers, has dedicated subcompartments with separate optical detection systems. This leads to increased sample volume, as well as an increase in cost for the equipment.

“In this study, we demonstrate that the applicability of a system originally designed for the purposes of imaging can be extended towards the performance of biochemical tests without any additional modifications to the hardware unit, thereby retraining the cost and laboratory footprint of the original device,” said study co-author Srinivasan Kandaswamy, from Sigtuple Technologies.

The haemoglobin testing solution is possible thanks to the design behind the microfluidic chip, a customised biochemical reagent, optimised imaging and an image analysis procedure specifically tailored to enable the high clinical performance of the medical diagnostic test. The automated microscope, which normally uses a combination of red, green and blue LEDs, used only the green LED during the haemoglobin estimation mode, because the optimised reagent (SDS-HB) complex absorbs light in the green wavelength.

The data obtained from the microfluidic chip in combination with an automated microscope was comparable with the predictions of haematology analysers (Pearson correlation of 0.99). The validation study showed the method meets regulatory standards, which means doctors and hospitals are likely to accept it.

Besides measuring haemoglobin in the blood, a similar set-up with minor modifications could be used to measure protein content, cholesterol and glycated haemoglobin. Indeed, chip-based microfluidic diagnostic platforms are on the verge of revolutionising the field of health care and colorimetric biochemical assays are widely performed diagnostic tests.

“This paper lays the foundation and will also serve as a guide to future attempts to translate conventional biochemical assays onto a chip, from the point of view of both chip design and reagent development,” Kandaswamy said.

Image credit: SigTuple Technologies.

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