Monitoring blood glucose

Understanding the differences between devices

Monitoring your blood glucose is a vital part of diabetes management.

Your diabetes care team will help you decide how often and when to check. Often people are told that they should check their blood glucose levels via finger stick at least four times if they don’t use a continuous glucose monitor (CGM) before each meal and at bedtime. And are also advised to check if they feel low or high before exercise or driving, or more often if you are sick (like with a cold or flu) or other unusual circumstances that may affect your blood glucose levels. Often people check over 10 times per day to try to keep their blood glucose in their target range.

However, people with T1D are more commonly using flash glucose monitors (Flash GMs) and CGMs that measure the body’s glucose levels in real-time by sensing the glucose present in tissue fluid (also called interstitial fluid). Here’s what you need to know about them:

Glucometer (glucose meter)

A Glucometer, or blood glucose meter, is commonly used to check blood glucose levels. This involves taking a small drop of blood, usually by pricking the fingertip, and placing it on the test strip in a glucometer. Blood glucose levels are measured in  mmol/L (millimoles per litre). The standard guidelines for a safe blood glucose range are: Fasting and before meals: 4.0 to 7.0 millimoles per litre (mmol/L) 2 hours after meals: 5.0 to 10.0 mmol/L or 5.0 to 8.0 mmol/L if A1c targets are not being met.

But depending on the person and the recommendation of their diabetes care team, sometimes the recommended target range is expanded

Tips for using glucose meters

When using a glucose meter to check your blood glucose levels, it’s important to have clean fingers, as the accuracy of your test can be impacted by the presence of food or contaminants on your fingers. For those times when you can’t wash your hands before you test, you may want to carry some finger wipes with you. However, if you do clean your finger first, be sure to have it dry before testing.

Just like insulin, glucose meters and strips can be affected by low (freezing) or high temperatures, so remember not to leave your blood glucose monitor in your car, in direct sunlight, or anywhere that gets extremely hot or cold. Some types of meters are more sensitive than others to high and low temperatures. See the insert in the meter package or visit the manufacturer’s website for more specific storage instructions.

It might be tempting to leave your glucometer at home; however, knowing how your blood glucose levels are trending will help you avoid instances of hypoglycemia (low blood glucose) and hyperglycemia (high blood glucose).  Remember to pack your lancing device too, it’s usually in the case with the meter so double check that you have it in it.

Lancet devices

When using a blood glucose meter, a lancing device is what holds a lancet or small, sharp object used to prick the skin for a blood sample. Carrying spare lancets for your lancing device (or using one of the new lancing devices that store multiple fresh lancets inside a drum) will reduce blunt lancet testing paint.

You have a choice when it comes to lancing devices, and you don’t necessarily have to use the one that comes with the meter. It’s fine to mix and match to find a lancing device that works best for you. If your metre is taking up too much space in your kit, have a look at the different sized meters available.

Flash glucose monitor (Flash GM) A flash glucose monitor is a small sensor worn under your skin. It is often called a Flash GM for short.

The Flash GM measures your blood glucose levels continuously throughout the day and night. You find out your levels by scanning the sensor whenever you want to.

This sensor doesn’t actually measure your blood glucose level, but the amount of glucose in the fluid surrounding your body cells – called interstitial fluid.

There is a small time delay when checking this fluid, particularly after eating or while exercising. So this result won’t be exactly the same as the finger-prick result. But it is a useful tool that can be accessed to check your levels quickly and easily.

Continuous glucose monitor (CGM)

The methods of checking blood glucose levels have seen major advancements in recent years. Case in point: CGMs. CGMs work by wearing a sensor just under the skin that measures the tissue-glucose levels in real time. The levels are then relayed to a receiver, smartphone or insulin pump which displays the readings. Learn more about the different types of CGMs and what they do by visiting the manufacturer’s website and asking questions about their functionalities with your diabetes care team.

Blood or urine ketone strips

Diabetic Ketoacidosis (DKA) can be a life-threatening condition. Ketones are caused by the breakdown of fat when there isn’t enough insulin to allow the glucose (sugar) into your cells for energy. When ketones build up, the result is acidosis (too much acid in the blood). If not treated, this can lead to death. Usually blood glucose levels are elevated to more than (7.0 mmol/L and above ) but not always. It is important to have a way to check for ketones, either using urine strips or blood test strips with a ketone-testing device, to help identify whether you are at risk of ketoacidosis.

Sharps container

A sharps container is essential for safely disposing of used pen needles, syringes, or lancets. Medical sharps containers are available from pharmacies.

There is much technology available for people with T1D. Discuss with your diabetes healthcare team to decide what technology is right for you.