How to Understand Preprandial Blood Sugar Readings

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Preprandial means "before a meal." You might have heard the word in the context of preprandial plasma glucose. This refers to your blood sugar levels before a meal. It may also be known as the fasting blood glucose level (if you haven't eaten in at least eight hours). Postprandial blood glucose, on the other hand, refers to your blood sugar levels one to two hours after eating.

What Are Normal Preprandial Glucose Levels?

For healthy adults, normal preprandial glucose levels are 70 - 99 mg/dl. A preprandial glucose reading of 100 - 125 mg/dl indicates prediabetes.

For adults with diabetes, the American Diabetes Association recommends a preprandial glucose target of 80–130 mg/dl. The American Association of Clinical Endocrinologists suggests a preprandial glucose goal of <110mg/dl for people with diabetes.

However, depending on your personal health condition, your doctor may set preprandial glucose readings that are different than these guidelines, so make sure you know what numbers you're shooting for.

Why Do Preprandial Plasma Glucose Readings Matter?

Your preprandial plasma glucose readings tell you the amount of glucose in your bloodstream when you haven't eaten. 

When you eat, the carbohydrates (and a small amount of the protein) that you've ingested change into glucose, which gets absorbed into your bloodstream. In response, your pancreas releases insulin, which helps move glucose out of the bloodstream and into cells where it can be used as energy. In a healthy state, your body regulates the amount of insulin that's released, resulting in optimal blood sugar readings, ones that are neither too high (hyperglycemia) or too low (hypoglycemia).

In diabetes, this balance of insulin and glucose is disrupted.

In type 1 diabetes, that's because the pancreas stops making insulin, so your body can no longer bring glucose into the cells and your blood sugar levels get very high. In this case, you need to take insulin through an insulin pump or injections.

In type 2 diabetes, the pancreas either isn't making enough insulin, or your cells become resistant to insulin, so it's less effective at bringing glucose from the blood into your cells. This type of diabetes can be managed through diet, exercise, medication and, if needed, insulin.

How to Preprandial Plasma Glucose Readings

When you have diabetes, it's important to check your blood sugars before and after you eat. In addition, you should also keep a record so you can get a sense of your blood sugar trends over time (and figure out what's influencing your blood sugar — what you ate, how much exercise you got, your stress levels). Doing so can help you and your doctor know how well your treatment is working. It can help you adjust your behaviors in the short term so that you won't be surprised by your long-term glucose control. Your blood glucose control over time is measured by the A1C. Keeping preprandial or fasting blood glucose levels close to normal often can determine a good A1C outcome. Having an A1C in the normal range can help to reduce the risk of diabetes complications. 

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