Glucose monitor accuracy questioned

Glucose monitor accuracy called into question

Certain self-monitoring blood glucose systems, even though they meet accuracy standards upon FDA clearance, fail to consistently meet those standards once on the market, according to the Diabetes Technology Society (DTS).

At a DTS meeting last week in Arlington, Va., academic clinicians, clinical chemists, medical device experts, patient advocates and FDA officials examined several peer-reviewed studies that show the performance of some glucose monitors failing to meet accuracy standards – and posing a risk for patients.

"We have a problem, particularly with some low-cost glucose meters," said David Klonoff, MD, president of DTS and clinical professor of medicine at the University of California, San Francisco, in a press statement. "Meters help patients to make important decisions about how to treat their diabetes – everything from diet and exercise to determining how much insulin to take."

Inaccurate meter readings, of course, can lead to inaccurate doses of insulin.

"Too much insulin can bring blood glucose levels down to dangerously low levels, putting the patient at risk of a hypoglycemic event or hospitalization," said Klonoff. "It's going to be critical that industry, clinicians, academicians, regulators and the diabetes community continue to work to ensure every patient has an accurate meter they can rely on."

DTS panelists reviewed several reports suggesting that blood glucose monitors do not consistently meet accuracy standards after FDA clearance:

  • A study presented by Guido Freckmann, MD, of the Institut für Diabetes Technologie in Germany, published in the Journal of Diabetes Science and Technology evaluated 34 self-monitoring blood glucose systems and found that seven did not meet current accuracy standards.
  • Another of Freckmann's studies showed there was considerable variability between SMBG test strip lots with three of the five systems studied, and only two systems met accuracy standards with each test strip lot.
  • A third report, by Ronald Brazg of the Rainier Clinical Research Center in Renton, Wash., found that just three of seven SMBG systems tested consistently met current accuracy standards.

Until recently, the international standard for blood glucose monitoring, known as the ISO standard, required that 95 percent of normal or elevated readings by blood glucose monitors be within plus or minus 20 percent of the true value, DTS officials pointed out.

New international standards for blood glucose are expected to require 95 percent of normal or elevated readings by blood glucose monitors fall within plus or minus 15 percent of the true value.

FDA officials said at the DTS meeting that the administration would be issuing new formal guidance on accuracy standards to guide product development and ensure the safety of products currently on the market.