A non-invasive monitoring device to detect dangerous drop in white blood cells

Researchers funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) have developed a portable, non-invasive monitor that can determine, in one minute and without drawing blood, whether chemotherapy patients have a reduced number of white blood cells that could lead to infections.

An MIT research team visited a chemotherapy unit as part of a special Massachusetts Institute of Technology (MIT) program designed to identify and solve relatively common, yet significant problems in healthcare settings. They learned that chemotherapy causes a reduction in infection-fighting white blood cells, and about 17% of the time this results in infectious disease, which at worst can result in death and at best causes setbacks in the patient’s chemotherapy regime while the infection gets treated.

The research team led by Carlos Castro-Gonzalez, Ph.D., a postdoc in MIT’s Research Laboratory of Electronics, determined that a device to monitor white blood cell levels at home, following chemotherapy, would allow these patients to easily detect dangerous drops in white cells. This would enable immediate treatment with agents that increase white cell production, and prophylactic antibiotics. Their work is described in the journal Scientific Reports.

The tabletop prototype device, designed to be used easily at home, takes a video of blood moving through extremely small capillaries at the base of the fingernail just below the skin. The system takes advantage of the fact that white blood cells are much larger than the red cells flowing through capillaries and are almost exactly as wide as the capillary—about the width of a human hair.

The blue light used in the device makes the red cells appear dark and the white cells appear transparent. Because the white cells completely fill the width of the artery as they flow through it, they appear as a white “gap” in the dark flow of red blood cells moving through the capillary. The gaps can be easily counted and any reduction in the normal number of white cells expected to pass through the capillary can be detected in just one minute. In the initial testing of the device the white cells were visually counted by observers, but the research team is currently adding automated computer counting to the system.

“This is a simple, yet highly effective technological solution to a common problem in cancer care that will improve cancer treatment at local clinics and at home,” said Tiffani Bailey Lash, Ph.D., director of the NIBIB program for Point of Care Technologies. “It is an excellent example of the NIBIB’s emphasis on point of care technologies that can both reduce healthcare costs and also bring care to remote and underserved communities.”

“Our system proved to be 95 percent accurate in determining whether an individual’s white cell levels were reduced to dangerous levels,” said Castro-Gonzalez. “This was achieved using the counts of our human observers; preliminary results indicate that the automated machine-vision counting system we are developing can improve this level of accuracy.”

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