Credit: Максим Кукушкин
Researchers have developed an optical device that requires only a few drops of blood and a few minutes to measure coagulation parameters that can guide blood transfusions and anticoagulant therapy.
The team described their device in Biomedical Optics Express.
“Currently, the most comprehensive measures of coagulation are a battery of lab tests that are expensive and can take hours to perform,” said study author Seemantini Nadkarni, PhD, of Massachusetts General Hospital in Boston.
She noted that other systems have been developed that provide clotting measurements at the point of care, but the systems can be big and expensive or have other limitations, such as requiring significant amounts of blood or only measuring clotting time.
“Our goal is to provide as much information as a lab test, but to provide it quickly and cheaply at a patient’s bedside,” Dr Nadkarni said.
To reach this goal, she and her colleagues turned to an optical technique they pioneered called laser speckle rheology. The technique involves shining a laser into a sample and monitoring the patterns of light that bounce back.
The researchers had previously used the technique to measure the mechanical properties of a range of different tissue types and found that it was extremely sensitive to the coagulation of blood.
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, a speckle pattern, fluctuate rapidly.
“It’s almost like looking at a starry night sky, with twinkling stars,” Dr Nadkarni said. “But 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 gets stiffer, and the ‘twinkling’ of the speckle pattern is reduced significantly.”
Dr Nadkarni and her colleagues used a miniature high-speed camera to record the fluctuating speckle pattern and then correlated the intensity of changes in the pattern with 2 blood sample measurements: clotting time and fibrinogen concentration.
The team noted that physicians could use the measurements to make decisions about how much blood to give a bleeding patient and what type of blood product is needed most.
“The timely detection of clotting defects followed by the appropriate blood product transfusion is critical in managing bleeding patients,” Dr Nadkarni said. “If you transfuse too much, there could be further coagulation defects that occur, but if you don’t transfuse enough, bleeding continues.”
On the other end of the spectrum, the device could help patients on anticoagulant therapy. Having a small device that can analyze their blood in a doctor’s office or at home could reduce the cost and inconvenience of blood tests, while increasing the safety of anticoagulation treatment, Dr Nadkarni said.
At present, her team’s device is about the size of a tissue box and is connected to a computer. The researchers are working to further miniaturize the system and aim to perform clinical studies with a version smaller than a cell phone within the next year.
