I love the idea of people with diabetes having more options to fit their lifestyle. Blood glucose testing is necessary to gather information to gain the best blood glucose control possible. Many people like to give their fingers a break, and I understand that. What I don’t like are the misleading ads that give patients false hope when they say things like, “it’s a meter where you don’t have to prick your finger.” It makes you think there is a testing device that works perhaps with a laser, but certainly without drawing blood. And that is just not true — at least not where these ads are concerned.
The ads are referring to alternate site testing, which means drawing blood from non-fingertip sites such as the palm, forearm or even the upper arm. There are certainly advantages to this type of blood testing, which include less pain and the ability to prevent callus formation by testing too much in one place. But there are some facts people need to know about alternate site testing and why it may not be as accurate as fingertip testing in certain cases.
When your blood sugars are falling or rising rapidly — such as after exercise, following a meal, or when you suspect a low blood sugar — alternate site testing may not be your best option for analyzing blood glucose. This is simply because blood glucose utilization in different areas of the body vary, and fingertip blood seems to correlate with the most current state of your actual blood glucose. Blood glucose readings give us important information, such as how much insulin to take, how many carbs we should or should not eat, and whether or not it’s all right to engage in physical activity. Getting it right is critical.
I am in no way saying alternate site testing is bad; for many patients, it’s a great option. Knowledge is power and my goal is to empower you. If you use alternate site testing, do it when blood sugars are relatively stable — such as right before a meal, when you take a fasting blood sugar or near bedtime. At times when blood sugars may be rapidly changing such as following a meal, after exercise or when you think you have a low blood sugar fingertip testing may be best because of accuracy. Remember also that only certain blood glucose meters are “approved” for alternate site testing, so check with the manufacturer if you are uncertain about if your meter can be used in this way. There are smaller blood samples from alternate sites and not all meters are equipped to handle this accurately.
Blood glucose monitoring has revolutionized diabetes care. There is no better way to know how well controlled you are than by testing blood glucose levels at home. Remember to never ignore symptoms of low blood sugar. If alternate site testing does not match how you feel, test again with a fingertip sample. Stay informed and always check with your health care team before you try anything new.