Mumbai: A drop of blood, a glass slide and a ruler may soon be enough to screen for two serious blood disorders in villages far from any laboratory. A research team from the Department of Chemical Engineering at the Indian Institute of Technology Bombay (IIT Bombay), led by Professor Mahesh Tirumkudulu, has developed a simple, low-cost point-of-care approach that uses the length of a blood smear — the distance a drop of blood spreads across a glass slide — to detect anaemia and to detect and monitor treatment for sickle cell disease, IIT Bombay said. The study, whose first author is Dr Mahrukh Mir, a former PhD scholar in Professor Tirumkudulu's lab, with Bhavesh Raicha of Valsad Raktdan Kendra as co-author, is published in the journal Lab on a Chip.

Source: Research Matters (IIT Bombay research news)

The physics is straightforward: thicker, more viscous blood spreads less and leaves a shorter, thicker smear, while thinner blood spreads further. Because hand-made smears vary from technician to technician, the team built its own patented automated device that holds two slides at a fixed angle and draws the upper slide off at a controlled speed, so every smear is made the same way. Anaemia lowers red blood cell concentration and haemoglobin, making blood less viscous; sickle cell disease makes red blood cells rigid when oxygen is low — and both changes show up in how the blood flows.

Source: Medical Buyer

95.1%Severe anaemia cases correctly identified in a 516-person study
394People in sickle cell field trials in tribal Maharashtra and central India — about 95% classified correctly
1 dropBlood needed for the test — plus a pipette, slides, a cheap chemical and a ruler
No labNo laboratory or specialist needed to run the screening

For anaemia, the researchers studied 516 individuals and found the method correctly identified 95.1% of people with severe anaemia (haemoglobin below 8 g/dL) and 86% of those without it, estimating haemoglobin to within about ±0.8 g/dL; a companion imaging method that reads the colour of the dried smear did even better on more than 1,000 patients, at about ±0.5 g/dL. For sickle cell disease, the sample is first deoxygenated with an inexpensive chemical, sodium metabisulfite: in field tests on 394 people, blood viscosity rose by less than 17% after deoxygenation in healthy people, by 17 to 70% in trait carriers and by more than 70% in people with full disease — a separation clear enough to classify about 95% correctly. The test could also track whether the standard drug hydroxyurea is working, as treated patients' viscosity rise fell from around 125% to about 70%.

Source: Elets eHealth

The researchers are candid about the limits: viscosity cut-offs can differ between population groups because of genetic variation, and the anaemia screen could miss rare cases, such as hyperviscosity syndrome, where the usual link between viscosity and anaemia breaks down. The technology has been licensed to Rheoheme Private Limited, an IIT Bombay startup, and the team is working with the ICMR National Institute for Research in Tribal Health in Jabalpur and AIIMS Nagpur toward regulatory approval, while exploring whether the same platform can measure clotting time and blood glucose. Sickle cell disease is prevalent in India's tribal communities and often goes undiagnosed for want of testing facilities — the gap this device is designed to close.