- With Mayo Clinic endocrinologist
Maria Collazo-Clavell, M.D.
read biographyclose windowBiography of
Maria Collazo-Clavell, M.D.
Maria Collazo-Clavell, M.D.
Dr. Maria Collazo-Clavell is board certified in internal medicine, endocrinology, diabetes and metabolism. She's a consultant in the Division of Endocrinology, Diabetes, Metabolism & Nutrition at Mayo Clinic and an associate professor at College of Medicine, Mayo Clinic.
The Aibonito, Puerto Rico, native has been with Mayo Clinic since 1994.
She's a member of the American Association of Clinical Endocrinologists, the American College of Endocrinology, the American Diabetes Association and The Endocrine Society.
Dr. Collazo-Clavell is medical editor of diabetes content on Mayo's health information website and for "Mayo Clinic The Essential Diabetes Book." Her clinical interests include management of type 1 and type 2 diabetes, obesity and nutritional disorders.
Risk factors (1)
- Diabetes: Does alcohol and tobacco use increase my risk?
Symptoms (1)
- The dawn phenomenon: What can you do?
Complications (1)
- Diabetes: How do I help protect my liver?
Treatments and drugs (5)
- Avandia safety concerns: What should I do?
- Diabetes management: Does aspirin therapy prevent heart problems?
- Blood glucose monitors: What factors affect accuracy?
- see all in Treatments and drugs
Lifestyle and home remedies (11)
- Diabetes: Are electric blankets off-limits?
- Vegetarian diet: Can it help me control my diabetes?
- Air pollution and exercise: Is outdoor exercise risky?
- see all in Lifestyle and home remedies
Alternative medicine (1)
- Diabetes treatment: Can cinnamon lower blood sugar?
Prevention (2)
- Healthy heart for life: Avoiding heart disease
- Sodium nitrate in meat: Heart disease risk factor?
About our e-newsletters
- Free e-newsletters
- Mayo Clinic expertise
- We do not share your e-mail address
Housecall, our weekly general-interest e-newsletter, keeps you up to date on a wide variety of health topics with timely, reliable, practical information, recipes, blogs, questions and answers with Mayo Clinic experts and more. Our biweekly topic-specific e-newsletters also include blogs, questions and answers with Mayo Clinic experts, and other useful information that will help you manage your health.
Housecall Archives
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Question
Blood glucose monitors: What factors affect accuracy?
Sometimes my blood glucose monitor seems to give incorrect readings. What causes this, and what can I do to make sure the measurement is accurate?
Answer
from Maria Collazo-Clavell, M.D.
When used correctly, blood glucose monitors — small devices that measure and display your blood sugar level — are usually accurate. But occasionally they're incorrect. Inaccurate readings are usually due to human error rather than to a nonfunctioning or unreliable meter.
Consider these factors that affect meter accuracy and the steps to resolve or prevent the problem:
| Factors that affect accuracy | Solutions |
|---|---|
| Test strip problems | Throw out damaged or outdated test strips. Store strips in their sealed container; keep them away from heat, moisture and humidity. Be sure the strips are meant for your specific glucose meter. |
| Extreme temperatures | Keep your glucose meter and test strips at room temperature. |
| Alcohol, dirt or other substances on your skin | Wash your hands and the testing site with soap and water before pricking your skin. |
| Improper coding | Some meters must be coded to each container of test strips. Be sure the code number in the device matches the code number on the test strip container. |
| Monitor problems | Fully insert the test strip into the monitor. Replace the monitor batteries as needed. |
| Not enough blood applied to the test strip | Apply a generous drop of blood to the test strip. Don't add more blood to the test strip after the first drop is applied. |
| Testing site location | If you're using a site other than your fingertip and you think the reading is wrong, test again using blood from a fingertip. Blood samples from alternate sites aren't as accurate as fingertip samples when your blood sugar level is rising or falling quickly. |
Blood glucose monitor quality control tests
Quality control tests verify the accuracy of your blood glucose monitor. Perform these tests when you start a new container of test strips, occasionally as you use the container of strips, and when you think your results seem unusual.
To perform a quality control test, do one or both of the following:
- Test using a control solution. Follow your normal blood-testing procedure, but use a liquid control solution instead of blood. These solutions usually come with your monitor and are available at most drugstores and pharmacies. Follow package directions.
- Match your reading with lab results. Take the blood glucose monitor along when you visit your doctor or have an appointment for lab work. Check your blood glucose with your meter at the same time that blood is drawn for lab tests. Then compare your meter's reading with the lab results. Your meter's result is considered accurate if it falls within 15 percent of the lab test result.
After a flood, are food and medicine safe to use?
- Checking your blood glucose. American Diabetes Association. http://www.diabetes.org/type-2-diabetes/blood-glucose-checks.jsp. Accessed Oct. 8, 2009.
- Common problems with the use of glucose meters. U.S. Food and Drug Administration. http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/TipsandArticlesonDeviceSafety/ucm109449.htm. Accessed Oct. 9, 2009.
- McCulloch DK. Blood glucose self-monitoring in management of diabetes mellitus. http://www.uptodate.com/home/index.html. Accessed Oct. 9, 2009.
- Glucose testing device. U.S. Food and Drug Administration. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnostics/GlucoseTestingDevices/default.htm. Accessed Oct. 19, 2009.
Find Mayo Clinic on