Blood Sugar (Glucose) Monitoring FAQs

If you have diabetes, keeping a close watch on your blood sugar (glucose) helps you manage your condition and avoid complications. Glucose monitoring can help you make choices about the foods you eat, your physical activity and your medications.

How does a glucose monitor work?

Portable blood glucose meters (or glucometers) work by measuring blood sugar levels in small amounts of blood. A lancet is used to prick the skin (usually a fingertip), and a small drop of blood is placed on a test strip, which the meter reads to calculate blood sugar.

Continuous glucose monitors (CGMs) are wearable devices that automatically measure glucose in body fluids (called interstitial fluids). A tiny sensor beneath the skin measures glucose every 5-15 minutes, sending readings to a wireless monitor. CGMs can be worn day and night to detect trends and send warnings about abnormal levels. Insulin pumps can be linked with CGMs for continuous care. A glucometer should still be used daily to make sure CGM readings are accurate.

Ask your Mercy endocrinologist which glucose monitoring method is right for you.

Does insurance cover glucose monitors?

Health plans vary on the types and amounts of diabetic supplies they cover. Check with your health plan about what’s covered and any out-of-pocket costs.

Do Medicare or Medicaid cover glucose monitors?

It depends on your individual coverage, and some policies vary by state.

  • For Medicare assistance, call 1.800.MEDICARE (1.800.633.4227) or visit medicare.gov
  • For Medicaid assistance, contact your state’s Medicaid agency; for a list by state, visit medicaid.gov

How accurate are glucose monitors?

Glucose monitors sold in the U.S. require approval from the Food and Drug Administration (FDA). To receive FDA approval, these devices must be proven safe and effective. The FDA recommends avoiding glucose monitors or supplies sold outside the U.S., which may not be as effective or accurate.

Why should you monitor blood glucose levels?

If you have diabetes, glucose monitoring helps you manage your condition. Checking your blood sugar regularly will tell you:

  • Which foods make your blood sugar rise
  • How exercise affects your glucose level
  • Whether your diabetes medicines are working
  • How illness, pain, stress and other factors affect your blood sugar

Do blood glucose monitors measure ketones, too?

Some monitors measure both glucose and ketones (blood acids). Ask your Mercy endocrinologist when and how you should check for ketones.

High levels of ketones in people with diabetes can cause diabetic ketoacidosis (DKA), a life-threatening condition. When the body doesn’t have enough insulin to use glucose (its normal energy source) ketones build up in the blood, making it more acidic. High ketone levels are a sign diabetes is out of control. DKA may lead to severe complications like diabetic coma.

Find an Endocrinologist

Mercy has diabetes specialists across most of our communities.

Find an endocrinologist near you.