As of June 2015, the only glucose meter that doesn't require skin pricking involves an under-the-skin sensor that must be replaced every three to seven days. The device continuously monitors blood sugar levels and sends an audible alarm when glucose levels become too high or too low, says Mayo Clinic.
Researchers at the Hong Kong Polytechnic Institute are developing a noninvasive glucose tester. As of 2015, it is not yet available to the public, according to About.com.
Newer varieties of glucose meters available for diabetics use very small amounts of blood for testing, notes About.com. Most models require 1 microliter of blood to obtain an accurate blood sugar reading.