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New Microchip Test Diagnoses Type-1 Diabetes
Researchers at the Stanford University School of Medicine have developed an inexpensive, portable, microchip-based test for diagnosing type-1 diabetes that could speed up diagnosis and enable studies of how the disease develops.
Described in a paper published online July 13 in Nature Medicine, the test employs nanotechnology to detect type-1 diabetes outside hospital settings. The handheld microchips distinguish between the two main forms of diabetes mellitus, which are both characterized by high blood-sugar levels but have different causes and treatments. Until now, making the distinction has required a slow, expensive test available only in sophisticated health care settings. The researchers are seeking FDA approval of the device.
“With the new test, not only do we anticipate being able to diagnose diabetes more efficiently and more broadly, we will also understand diabetes better — both the natural history and how new therapies impact the body,” said senior author Brian Feldman, MD, PhD.
A growing body of evidence suggests that rapid detection of, and aggressive new therapies for, type-1 diabetes benefit patients in the long run, possibly halting the autoimmune attack on the pancreas and preserving some of the body’s ability to make insulin.
The older, slower test detects the auto-antibodies using radioactive materials, takes several days, can be performed only by highly trained lab staff, and costs several hundred dollars per patient. In contrast, the microchip uses no radioactivity, produces results in minutes, and requires minimal training to use. Each microchip, expected to cost about $20 to produce, can be used for more than 15 tests. The chip also uses a much smaller volume of blood than the older test; instead of requiring a lab-based blood draw, it can be done with blood from a finger prick.
The microchip relies on a fluorescence-based method for detecting the antibodies. The team’s innovation is that the glass plates forming the base of each microchip are coated with nanoparticle-sized islands of gold, which intensify the fluorescent signal, thereby enabling reliable antibody detection. The test was validated with blood samples from people newly diagnosed with diabetes and from people without diabetes. Both groups had both the prior test and the microchip-based test performed on their blood.
In addition to new diabetics, people who are at risk of developing type-1 diabetes, such patients’ close relatives, also may benefit from the new test because it will allow doctors to quickly and cheaply track patients’ auto-antibody levels before they show symptoms. Because it is inexpensive, the test may also allow the first broad screening for diabetes auto-antibodies in the population at large.
“The auto-antibodies truly are a crystal ball,” Feldman said. “Even if you don’t have diabetes yet, if you have one auto-antibody linked to diabetes in your blood, you are at significant risk; with multiple auto-antibodies, it’s more than a 90% risk.”
Source: Stanford University School of Medicine; July 13, 2014.