College of American Pathologists
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  Shorts on Standards


CAP Today




March 2011

The CAP has 30 official liaisons to various organizations who attend scientific meetings or designate others to do so. They report to the Standards Committee, which reports to the Council on Scientific Affairs. We publish periodically bits of what the CAP’s outbound liaisons hear and see in their liaison roles.

Glucose meters for TGC may need tightening

William J. Castellani, MD
David B. Sacks, MBChB

In vitro diagnostic devices represent a major international market, one that is currently strongly influenced by the Food and Drug Administration. The European Union promoted its own requirements for such devices in the 1990s through the European In-vitro Diagnostics Directive. Recognizing that European requirements would have an international impact in the marketplace (similar to the FDA’s impact through U.S. regulation), the European Union agreed to work with the International Organization for Standardization, or ISO, to promote international standards through Technical Committee 212. The FDA also agreed to respect the standards developed through TC 212, specifically Work Group 3.

Glucose meters for home testing were the first devices for which this work group established performance standards, specifically for “self-testing in managing diabetes mellitus,” and these standards form the basis for FDA approval of such devices in the U.S. under the waived testing category. This standard is now up for revision by the Project Team on Blood Glucose of TC 212 Work Group 3.

The current version of the standard specifies a minimum acceptable accuracy for results produced by a glucose monitoring system, depending on the glucose level. It requires that 95 percent of the individual glucose results fall within 15 mg/dL at target glucose concentrations less than 75 mg/dL, and within ±20 percent at glucose concentrations greater than 75 mg/dL. Although the FDA has strongly backed tightening these acceptability limits in the revision of the standard, instrument manufacturers, regulators, and end users have not agreed on what these new limits should be.

Following a project team meeting in Washington, DC, in January 2010, the FDA proceeded with an independent evaluation of the criteria to be used in the United States, especially for devices designated for “professional use.” This distinction is important. The original standard was developed for glucose meters used by diabetic patients for self-monitoring; these instruments may not be appropriate for hospital inpatient use, especially when monitoring nondiabetic critically ill patients in the context of tight glycemic control.

Although an informal consensus has developed for tightening the range of acceptability at normal and elevated glucose levels to ±15 percent, further refinement of this issue and others associated with the validation of these devices will be considered in subsequent meetings of this project group. These include performance evaluation, interference assessment, and alternative site testing. The FDA’s input will have a significant impact on the final standard, both in establishing regulatory requirements for the United States and because the FDA has been and will be a U.S. participant in the project group.

The CAP is co-sponsoring the 29th Arnold O. Beckman Conference, presented by the American Association for Clinical Chemistry and the National Academy of Clinical Biochemistry. This conference, which will be held next month in San Diego in conjunction with the annual meeting of the American Association of Clinical Endocrinologists, will examine the many issues surrounding tight glycemic control in critically ill patients.

Dr. Castellani, a member of the CAP Standards Committee, is in the Department of Pathology at Penn State Hershey Medial Center. He is the CAP’s liaison to ISO TC 212 Work Group 1. Dr. Sacks, chief of clinical chemistry in the National Institutes of Health Department of Laboratory Medicine, is a member of the CAP’s Chemistry Resource Committee.