Choosing Blood Glucose Monitors
An array of blood glucose meters offers diabetic patients
more choices and more comfort

By Susanne J. Pavlovich-Danis, RN, MSN, ARNP-C, CDE
November 29, 2004

Consistent and accurate self-monitoring of blood glucose (SMBG) levels is a crucial component of diabetes management. Monitoring reveals how the body is responding to food, activity, and medications and provides valuable information necessary to adjust medication regimens, meals, and exercise programs. Many monitoring meters are available, each with unique features that can enhance patient compliance and comfort and affect care planning. (See “Comparisons of widely used SMBG meters” sidebar.)

SMBG expense and discomfort have diminished in recent years. Meters are faster, smaller, and more user-friendly and sport more features that can help people with diabetes test themselves and even track trends, despite disabilities including visual deficits.

All meters are not created equal

Meters all use a whole-blood sample to test. However, newer machines are calibrated to display the readings as a plasma blood glucose level, the same as lab results from venipuncture. It’s important to know whether a patient’s meter readings are expressed as plasma or whole-blood values, because plasma-calibrated readings are 8% to 12% higher than readings expressed as whole-blood values.^1,2

Cleaning and calibrating are other important issues. Some meters still require the user to partially disassemble, clean, and reassemble them. Most newer meters require only periodic wiping of the outside with a damp cloth. Although many meters still require calibration and testing with a control solution for each new package of strips, some newer meters do not require this step.

Meter performance can differ with the environment.¹ Patients living in very hot or cold climates should be instructed to test indoors to improve accuracy. When exposure to temperature extremes is inevitable, such as ski trips to Vermont or hikes in the Grand Canyon in August, encourage patients to test before venturing out.

Altitude is another important factor. Forewarn patients with diabetes who travel that in-flight testing may be inaccurate. No meter is available to accurately test at altitudes above 10,400 feet.³ Encourage patients to test their blood before takeoff to gauge their glucose status.

Strips or drums?

Most meters use individual testing strips inserted at the time of testing. In the past, large droplets of blood had to land exactly on the right spot of the test strip pad for an accurate result. The process was often painful, messy, and difficult. Many patients wasted strips, became frustrated, and tested less often than recommended.

Newer strips require pinhead-sized blood samples, and many have a vacuum-type design that “sucks up” the exact amount of blood necessary for testing.

Some meters use multiple-test drums or cylinders, making testing easier for patients with limited dexterity, such as those with neurological conditions like Parkinson’s disease. Lancet devices, however, remain difficult for some patients to use.

Spare that fingertip

People with diabetes have come to expect sore fingertips, but new technology has turned painful fingertips into a bad memory for some. Many patients now use alternative site testing from areas such as the forearm, abdomen, or thigh. Before recommending alternative site use, however, refer patients to their primary diabetic care provider to be sure no contraindications exist. Keep in mind that alternative sites are not as accurate for testing when hypoglycemia occurs.¹

The amount of blood required for testing is an important consideration. Meters requiring larger droplets typically require a larger-sized (and more painful) lancet for specimen procurement. It’s also important to remind patients to rotate fingers used and obtain fingerstick blood samples from the side of the finger rather than from the more sensitive pad of the fingertip.

At the most expensive end of the glucose testing spectrum is the Glucowatch — a noninvasive meter worn as a wristwatch for up to 13 hours. This instrument does not require a fingerstick. Every 10 minutes, the watch takes a reading using a sensor pad that is placed on but does not penetrate the skin.⁴

Special features for special needs

Meters vary in size. Most are now conveniently small enough to tuck into a pocket or change purse. Some meters come with software programs that permit storage and tracking of readings on a personal computer. This feature can enhance recognition of blood glucose level patterns and provide valuable information to adjust oral medications or insulin therapy to cover periods of hyperglycemia and reduce the risk of hypoglycemia.

Some meters have larger display screens more easily viewed by the visually impaired. One meter even talks to the patient.

Expenses for supplies can be a significant barrier to consistent SMBG testing. Costs for meters and supplies vary widely based on features. Still. market competition and rebates can dramatically reduce or eliminate the actual cost of the meter. It is usually more important to evaluate the cost of test strips.

Comparisons of widely used SMBG Meters



For larger table:
http://nurseweek.com/news/images/Clinical_GlucoseMonitors_table_11-29-04.pdf
(38K, requires Adobe Acrobat).

Start out right and troubleshoot

Regardless of the patient’s educational level, every meter has a learning curve. Patients need initial education that includes return demonstrations to ensure proficiency. Of course, education must also include machine calibration, maintenance, and cleaning, if required. Don’t forget universal precautions and sharps disposal. Many companies provide videotapes to assist in patient training.

Patients experiencing problems with glucose meters must know how to contact the manufacturer. Most manufacturers offer 24-hour, toll-free assistance, and company representatives can guide patients through many problems, often in many languages. Serious problems concerning the glucose meter can be reported directly to the Food and Drug Administration at www.fda.gov/diabetes/glucose.html.

How nurses can help

Feedback is an important aspect of SMBG. Sometimes, patients are expected to self-monitor with little or no input about their readings. Encourage patients to record and track their readings and bring their logbooks with them whenever they visit their diabetes care provider or any other health care provider.

The most common reason for inaccurate SMBG testing is user error. Some of the more commonly reported reasons for errors are insufficient blood samples, incorrect meter calibration, a dirty meter, or defective or expired strips. Nurses can troubleshoot these problems and assist patients to use their machines properly.

Close monitoring of blood sugar is important to control diabetes and reduce the risk of long-term complications. Meters are not perfect, so remember to teach patients the warning signs and corrective actions for hypo- and hyperglycemia. A variety of testing meters and devices are available, each with unique features that can meet individual needs and preferences. Patients often seek advice from their nurses about routine care and equipment, and nurses who care for people with diabetes, must become familiar with several different meters and resources.

For additional information, visit “Glucose Meters and Diabetes Management” — a component of the U.S. Food and Drug Administration’s diabetes website at www.fda.gov/diabetes/glucose.html.

Susanne J. Pavlovich-Danis, RN, MSN, ARNP-C, CDE, maintains a private adult health practice in Plantation, Fla. She is also a professor and area chair for nursing at the University of Phoenix, Fort Lauderdale, Fla.

References

1. U.S. Food and Drug Administration website. Glucose meters and diabetes management. Available at: www.fda.gov/diabetes/glucose.html#11. Accessed October 27, 2004.

2. Havas S, Mayfield J. Self-control: a physician’s guide to blood glucose monitoring in the management of diabetes [American Family Practice Monograph]. Leawood, KS: American Academy of Family Physicians; 2004.

3. David Mendosa website. 10 reasons you love your meter so much. Available at: www.mendosa.com/10_reasons.htm. Accessed October 27, 2004.

4. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH. Noninvasive blood glucose monitors. Available at: http://diabetes.niddk.nih.gov/ dm/pubs/glucosemonitor/. Accessed October 27, 2004.

.