Scientists at MIT have developed a portable device that can measure white blood cell levels in chemotherapy patients without having to take a blood sample. The device can visualize blood cells flowing through capillaries in the nail bed and determine if white blood cell levels are at acceptable or dangerously low levels.
Chemotherapy can have significant immunosuppressive effects. In many patients, white blood cell counts can drop to dangerously low levels following a course of chemotherapy, leaving them at significant risk of serious infections. “In the U.S., one in six chemotherapy patients ends up hospitalized with one of these infections while their white cells are particularly low,” said Carlos Castro-Gonzalez, one of the researchers involved in the study.
However, clinicians typically test white blood cell levels just before administering a new dose of chemo, meaning that they have no way of knowing if dangerous immunosuppression is happening right after therapy.
The device developed at MIT may allow patients to test their own white blood cell levels at home, without the need for blood sampling. “Our vision is that patients will have this portable device that they can take home, and they can monitor daily how they are reacting to the treatment. If they go below the threshold, then preventive treatment can be deployed,” said Castro-Gonzalez.
The device consists of a microscope that patients can use to visualize capillaries in the skin at the base of their finger nail. The microscope emits blue light which penetrates to approximately 150 microns below the skin and is reflected back to a camera that records the image.
A computer algorithm then analyzes the images and can determine if white blood cell levels are below an acceptable threshold. While the technique does not result in a precise blood cell count, it lets patients know if their white blood cell count is dangerously low, allowing them to notify their doctor and take preventative action to avoid an infection.
So far, the researchers have tested the device in 11 patients undergoing chemo, and the technique was 95% accurate in identifying if levels of white blood cells were above or below the threshold. The research team is currently working on improving and commercializing the technique.