Researchers develop portable monitor 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. They estimated that this approach could prevent about half of the 110,000 infections that occur in chemotherapy patients in the U.S. each year. 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."

The group tested the device with 11 patients undergoing chemotherapy treatment. One minute of video was recorded while the patients finger was placed in the portable tabletop device. The number of white cells that passed through a single capillary were counted to determine whether chemotherapy treatment had reduced the white cell levels to below the threshold where the risk of infection increases.

"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."

The team is enthusiastic about the significant improvement in the lives of chemotherapy patients their monitor will provide. They are moving quickly to commercialize the technology by applying for patents and recently launched a company called Leuko, which is working on adaptations of the technology. One goal is achieving more precise white blood cell measurements that could be used to monitor the health of bone marrow recipients. Very precise white cell measurements could also be used to determine exactly when a chemotherapy patient could undergo their next treatment, which would allow for a safely compressed therapy schedule that could translate into more successful treatment and increased survival.