Vol. 20 • Issue 6 • Page 49
Lab Limelight
Blood glucose monitoring evaluates the concentration of glucose in blood and is a critical component of diabetes mellitus care. Tests are performed by piercing the skin to draw and apply blood to a chemically active test strip.1
Small handheld devices-glucometers-can measure blood glucose. To get accurate readings, it is important to make sure the glucose meter is operating correctly by applying quality control (QC) material to the strip, often sold separately for home glucometers, says Frederick L. Kiechle, MD, PhD, director of Clinical Pathology, Pathology Consultants of South Broward, Memorial Healthcare System, Hollywood, FL.
“Those values are used to adjust their dose of medication if the glucose is elevated-greater than 180 mg/dL, or low-less than 80 mg/dL,” Dr. Kiechle says. In such cases, diabetes patients can adjust their next insulin dose.
POC Testing
In a hospital setting, many facilities have instituted point-of-care (POC) glucose testing to get a rapid bedside result. Dr. Kiechle advises hospitals that move to POC devices create a steering committee to ensure QC and training of personnel. He says ideally medical technologists should be responsible for POC devices since the machine is really a small laboratory device, but even if nurses are in charge, “someone in pathology should take an interest in what is going on” in terms of keeping the device current, handling repairs, troubleshooting, QC and proficiency testing.
He encourages healthcare facilities to purchase one kind of glucose device system-wide so expertise can be shared and repeat errors can be avoided.
Occasionally vendors are needed for problems. For example, prepackaged wipes used to clean glucometers may leak liquid into an opening, causing an electronic malfunction.
Glucose Monitoring Products
FDA-approved glucose monitoring systems are available from Abbott Diabetes Care, Medtronic, Dexcom, Siemens Healthcare/Bayer Diagnostics, Roche Diagnostics, Nova Biomedical and HemoCue (a Quest Diagnostics company).
Dr. Kiechle says Nova Biomedical’s latest StatStrip® Xpress™ glucose monitor has “conquered the extremes of hemoglobin,” and the company’s website says StatStrip is the only bedside glucose meter to eliminate glucose errors (as large as 30%) due to hematocrit interference.
The HemoCue Glucose System is based on a glucose dehydrogenase method and consists of a small analyzer and disposable microcuvette.
CGM
Developing a noninvasive method to gauge blood glucose levels is an industry priority, Dr. Kiechle says. “Continuous monitoring is getting close, and I think those methods are improving,” he says.
Continuous glucose monitoring (CGM) systems use a tiny sensor placed under the skin for several days to a week to check glucose levels in interstitial fluid; a transmitter sends information via radio waves to a wireless monitor. Existing approved devices are less accurate than standard blood glucose meters and are more expensive but may enable better glucose control, according to the National Diabetes Information Clearinghouse.2
CGM devices are available from Abbott, DexCom and Medtronic to provide real-time measurements of glucose levels.2 Users can set alarms for too-high/-low glucose levels. Software enables data to be downloaded to a computer for tracking/analysis of patterns.
Future Developments
Future handheld glucose meters will need to be accurate and stable and have a coefficient of variation of 10% or less for use during tight glycemic control (80-120 mg/dL) for patients in the intensive care unit, Dr. Kiechle says. The protocol was a focus of a March 2010 FDA meeting in Gaithersburg, MD.
Furthermore, POC devices will need connectivity to the electronic medical record (EMR) and laboratory and hospital information systems. Dr. Kiechle mentions the Roche RALS®-Plus as a kind of middleware that captures patient identification and POC test result data and downloads it to the patient’s EMR.
Jill Hoffman is managing editor.
Related Products
Roche Diagnostics: RALS®-Plus from Roche Diagnostics is a connectivity solution to help users accurately capture patient ID and POC test result data, and seamlessly download it to the patient’s EMR. Developed by Medical Automation Systems (MAS), the program equips healthcare professionals to make the right treatment decision for the right patient at the right time. In addition to supporting patient safety initiatives by minimizing the potential for errors, Roche/MAS connectivity solutions help users save time, simplify regulatory documentation and streamline cost capture.
Nova Biomedical: The Nova StatStrip® Glucose Monitoring system features patented Multi-Well measuring technology, which elevates bedside glucose testing to a level of accuracy, precision and patient safety that approaches the quality of central laboratory testing, the company says. StatStrip is the only bedside glucose meter to eliminate glucose errors due to hematocrit interference, which can cause glucose errors as large as 30%. One of its four measuring wells measures hematocrit and corrects the glucose result for abnormal hematocrit levels.
HemoCue (a Quest Diagnostics business): Screening for elevated glucose levels helps identify individuals at risk for and who have diabetes, while ongoing glucose testing helps people with diabetes manage their glucose levels. Glucose tests also help detect neonatal hypoglycemia and maintain glycemic control during regular/intensive care. HemoCue’s first glucose system was released in 1991. Within its growing family of products, the HemoCue Glucose 201+ is a small, portable system that measures glucose levels in whole blood that can be used for diagnosing diabetes and monitoring glucose levels over time. The analyzer stores results and QC-tests, along with date/time.
References
1. “Blood glucose monitoring.” Wikipedia. Available at: http://en.wikipedia.org/wiki/Blood_glucose_monitoring (last accessed March 23, 2011).
2. “Continuous Glucose Monitoring.” National Diabetes Information Clearinghouse. Available at: http://diabetes.niddk.nih.gov/dm/pubs/glucosemonitor/index.htm (last accessed March 23, 2011).
3. Karon BS. Glucose meters in the ICU. ADVANCE for Administrators of the Laboratory 2011 January;20(1):14.
