Laser that quickly measures blood clotting at bed!

There are cases where people who met with an accident or underwent surgery died owing to defective blood coagulation.

Currently, the most comprehensive measures of coagulation are a battery of lab tests that are expensive and can take hours to perform.

To deal with this, researchers at Massachusetts General Hospital have developed an optical device that requires only a few drops of blood and a few minutes to measure the key coagulation parameters.

"The results can guide medical decisions, like how much blood to transfuse or what doses of anticoagulant drugs to administer," informed Indian-origin scientist Seemantini Nadkarni, an assistant professor at the Wellman Centre for Photomedicine at Massachusetts General Hospital.

"Our goal is to provide as much information as a lab test, but to provide it quickly and cheaply at a patient's bedside," Nadkarni added.

Nadkarni and her colleagues turned to an optical technique they pioneered called laser speckle rheology (LSR).

In LSR, researchers shine laser light into a sample and monitor the patterns of light that bounce back.

When light hits a blood sample, blood cells and platelets scatter the light.

In unclotted blood, these light scattering particles move easily about, making the pattern of scattered light - called a speckle pattern - fluctuate rapidly.

As the blood starts to coagulate, blood cells and platelets come together within a fibrin network to form a clot. The motion is restricted as the sample get stiffer, and the twinkling of the speckle pattern is reduced significantly.

Nadkarni and her team used a miniature high-speed camera to record the fluctuating speckle pattern.

"The timely detection of clotting defects followed by the appropriate blood product transfusion is critical in managing bleeding patients," Nadkarni said.

If you transfuse too much, there could be further coagulation defects that occur, but if you don't transfuse enough, bleeding continues, she added.

The device could also help patients whose blood coagulates too easily, forming clots inside of blood vessels in a condition called thrombosis.

These patients take anticoagulation medications and must regularly visit labs to have their blood analysed and the doses of the medications adjusted.

The research was published in the journal Biomedical Optics Express.