"I pulled from my enormous purse the small turquoise-pink-and-purple Peruvian bag that I use to carry meter, test strips, insulin, and syringes, and set it on the fold-out table in front of me. I began the process of getting out a test strip, lancing my fingertip, and lining up the drop of blood."
—Lisa Roney,
Sweet Invisible Body
Most diabetics test their blood glucose levels using a portable glucose meter, each measurement requiring a finger-prick, and a tiny drop of blood — a process that is sometimes repeated several times a day. Now, a new method using ultra-sound may take the sting out of such measurements.
"This method involves no needles and is completely painless. We think this will eventually make it easier for people to monitor their glucose levels," explains Robert Gabbay, assistant professor of medicine in Penn State’s College of Medicine. Keeping tabs on glucose levels is a part of the "constant balancing act," of diabetes, writes Lisa Roney in her memoir Sweet Invisible Body. When Roney was diagnosed with Type 1 diabetes in the 1970s, portable glucose meters didn’t exist. Only urine tests, crude as they were, allowed her to
monitor glucose levels at home. A more accurate reading required a nurse to draw a tube full of blood.
In the new procedure, low frequency ultrasound, about the same amount a dentist might use to clean teeth, is used to make the skin permeable so that glucose can cross the skin and be measured. Normally, explains Gabbay, the stratum corneum (dead layer of outside skin) provides a barrier to prevent things from crossing the skin. In the trial, however, a single burst
of ultrasound lasting less than two minutes is applied to the surface of the skin. The back of the forearm was used because it generally had less hair to interfere with the test. After that, glucose could diffuse across the skin and be measured continuously for the next 12 hours.
"We took blood from one arm of the patient to just be sure our new method had the correct results. Both methods had almost the identical readings," says Gabbay. "We used patients with Type 1 diabetes because they are dependent on insulin for the rest of their lives and must keep a close watch on their levels."
Keeping a close watch means being able to test glucose levels anywhere: at an office desk, at tables in restaurants, even while exercising outside. Gabbay explains that although the patients in his trial "were tested using an ultrasound machine that would typically be found in a research lab or hospital, a new hand-held device has been developed so patients could ultimately do the test at home.
"We know that by self-moni-toring the disease, and keeping glucose levels at a safe level, individuals can greatly reduce their chance of the disease giving them additional complications such as blindness or kidney failure," he notes.
The next step is trying the new method with a larger clinical trial, says Gabbay. He estimates that will happen later this year.
—Dana Bauer
Robert A. Gabbay, M.D., Ph.D., is assistant professor of medicine, College of Medicine, H044 Hospital Bldg., Hershey, PA 17033; 717-531-8395. Gabbay was co-author of a paper published in the March issue of the journal Nature Medicine. His work is supported by research grants from the ADA, Juvenile Diabetes Foundation, and the National Institutes of Health. Reported by Leilyn Perri, College of Medicine.
