Glucose Fasting (F) and Post Meal (PP) Test (Fasting & Post Prandial Blood Sugar Test)

Glucose fasting (F) and Post Meal (PP) Test (Fasting and Post Prandial Blood Sugar Test)

It is a simple blood test that is used to detect fasting blood sugar (FBS) levels and post prandial blood sugar (PPBS) levels. Here the sugar which is measured in blood is glucose. Glucose is the main form of energy which cells in the body utilise to do their work. Food that is eaten is broken down into simple glucose which is taken up the body cells with help of insulin (type of hormone) secreted by the pancreas.

Whenever there is decreased production of insulin or increased resistance of cells to the action of insulin, it causes increase in blood levels of glucose (also called hyperglycaemia) .This high levels of blood glucose can be due to a medical condition called diabetes/prediabetes. This condition is risky as it may cause damage to various organs of the body like heart, kidneys, intestine, eyes etc.

Low blood glucose levels (also called hypoglycaemia) may cause serious problems like brain damage if not managed on time.

Symptoms of hyperglycaemia are:

• Frequency of urination
• Increased thirst
• Increased hunger
• Visual disturbance
• Wounds that heal slowly

Symptoms of hypoglycaemia are:

• Sweating
• Anxiety
• Confusion

Why is fasting blood sugar and post prandial blood sugar test prescribed?

Your health care provider may order both these tests in following conditions:

• As a part of routine health check up to find if blood sugar before and after food is in normal range especially if you are over the age of 45years
• To detect diabetes or prediabetes if you have high risk factors like obesity, heart disease, hypertension, family history of diabetes and high cholesterol levels.
• To detect gestational diabetes (diabetes which occur during pregnancy)

What are the components of glucose fasting and post meal blood sugar test?

This includes two tests that are:

• Fasting blood sugar test-it is preferably taken in early morning after 8-12 hours of overnight fasting
• After meal blood sugar test-it is taken 2 hours after eating a meal. This is because within 2 hours of eating your blood glucose and insulin levels should return to normal range. If blood glucose is still high you may have diabetes

Procedure and prerequisites

The sample for fasting sugar test and post meal sugar test is taken from blood by inserting a small needle into vein of your arm. A small amount of blood is then collected in test tube or vial. You may feel some pain due to needle prick.

For fasting blood sugar test you need to fast for at least 8 hrs before the test. Overnight fasting is preferred with glucose fasting sample taken early next morning before having any food. Water intake is allowed before the test.

Post meal blood sugar test is done exactly 2hours after intake of moderate to heavy meals. The meal should have at least 75 grams of carbohydrates. After the meal don’t eat anything before the test.

Reference range

Fasting blood sugar-70-100 mg/dl is normal

Post Prandial blood sugar-<140 mg/dl is normal