24 Sep 2010

Diabetes Testing

Blood Sugar Testing
Introduction

To take care of your diabetes and your health, it is important to keep your blood sugar in balance. Self-monitoring of blood glucose on a regular basis is an important tool to help you do that. Sometimes you feel just fine, but only a blood sugar test can tell you if your blood sugar is in your target range.

Some feel that self-monitoring may be bothersome, inconvenient, even annoying, but testing will let you know if your meal plan, medicine, and activity are working for you. Self-testing is knowledge and knowledge is power. Knowing more about your blood sugar levels can help you and your healthcare team make better decisions about your overall diabetes management plan.

How Does Blood Testing Help Me Day-to-Day?

Research shows that keeping blood sugar levels in an acceptable target range helps prevent the complications associated with diabetes. You can lower your risk for eye problems, kidney disease, nerve damage, and heart problems. And, by understanding how you can manage your blood sugar levels, you can feel better day to day. High blood sugars can make you feel sluggish, and cause thirst and frequent urination. Low blood sugars can make you feel shaky and sweaty, and because low blood sugar requires immediate action, episodes of low blood sugar can significantly interrupt your day.

How Often Should I Test My Blood Sugar?

Many studies have shown that self-monitoring of blood glucose is helpful for people with either type 1 or type 2 diabetes. How often you test depends on the type of diabetes you have, and may vary from person to person. You and your healthcare team can decide on the optimal testing schedule for you.

When Should I Test My Blood Sugar?

The time of day that you test may vary from person to person and depends on your treatment plan. But, generally, you should test at times throughout the day when you need to know what your blood sugar level is; either to assess how a treatment is working or which therapy to take. Many people check their fasting blood sugar level first thing in the morning. This tells you how your medication worked overnight. Some people take medicine before meals to help control their blood sugar. If you take medicine before meals, you might want to check your blood sugar before and 2 hours after the meal to see how well that medication is working.

What is Postprandial (Post-Meal) Blood Sugar All About?

Even in people without diabetes, blood sugar goes up after a meal. For people with diabetes, this is often higher after meals than in those people without diabetes. Depending upon the meal and the amount of activity after the meal, the blood sugar comes back down over the next several hours. We don’t often think about the amount of time in a day that we are actually in a post-meal state, but actually at least half of the time people are in a postprandial state. The goal of diabetes management is to keep blood sugar levels as close to normal as possible without frequent episodes of low blood sugar. Research indicates that the postprandial period contributes significantly to the overall average blood sugar level (measured by A1c).

Why is Postprandial (Post-Meal) Testing Important?

In 2007 the International Diabetes Federation examined 4 very important questions:

  • 1)  Is postprandial (post-meal) hyperglycemia (high blood sugar) harmful?
  • 2)  Is treatment of postprandial (post-meal) hyperglycemia (high blood sugar) helpful?
  • 3)  What therapies are effective in treating post-meal blood sugar?
  • 4)  What are the targets for post-meal blood sugar and how should they be assessed?

The International Diabetes Federation issued guidelines that address all these questions from extensive research and expert opinion. It was determined that the after-meal blood sugar level is strongly linked to diabetes-related complications. So, in short, the answer to the first question is: Yes, post-meal high blood sugar is harmful.

Two major studies show that improved control of blood glucose can reduce the risk of complications associated with uncontrolled diabetes:

  • 1)  The Diabetes Control and Complications Trial, conducted in people with type 1 diabetes
  • 2)  The United Kingdom Prospective Diabetes Study, conducted in people with type 2 diabetes

Many other clinical studies also support the benefit of blood sugar control at all times of the day. Studies show that both the fasting and the post-meal blood sugar are important, and reaching target ranges cannot be accomplished without also addressing the post-meal blood sugar. So, in short, the answer to question 2 is: Yes, treatment of post-meal hyperglycemia is helpful.

There are a number of therapies that specifically target the post-meal blood sugar. Meal planning, physical activity, and weight control remain the cornerstones of diabetes management. Your post-meal test results provide important information about the effect your meal plan and even specific foods have on your blood sugar. Some oral medicines for people with type 2 diabetes specifically target post-meal glucose, and some types of insulin work to lower post-meal blood sugar level.

What Should My Post-Meal Blood Sugar Be?

The International Diabetes Federation and other organizations define normal glucose tolerance as 140 mg/dL (<7.8 mmol/L) two hours following ingestion of a 75 g glucose load. For people with diabetes, the post-meal glucose target is considered by some experts to be as low as 140 mg/dL (7.8 mmol/L) or up to 180 mg/dL (8 mmol/L). You and your healthcare team can determine your optimal target range.

When Should I Test My Post-Meal Blood Sugar?

Testing timeframes from 1 to 4 hours post-meal correlate with the A1c. However, the 2-hour timeframe is often recommended because it corresponds to the glucose guidelines established by most diabetes organizations and medical societies. The 2-hour measurement may be safer for people treated with insulin, too, to minimize the risk of over-treating a high blood sugar with an insulin bolus.

How Often Should I Test My Post-Meal Blood Sugar?

Self-monitoring of blood glucose allows people to obtain real-time plasma glucose information and is the best way for people to know and understand their diabetes management plan. Testing helps you make timely treatment choices to achieve and maintain a near-normal blood sugar level, and provides feedback about your diabetes management plan. The frequency of testing and the specific times of testing can be determined by you and your healthcare provider to help you feel well and live healthily with diabetes.

So, in summary, both fasting blood sugar testing and post-meal blood sugar testing are important and provide different information about your diabetes management plan. Establishing a testing routine that will help you best manage your diabetes will help you stay healthy and live well with diabetes.

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