Measurement of blood glucose is mainly divided into peripheral venous blood and peripheral blood. The time points of measurement mainly include pre- and postprandial blood glucose. Depending on the timing, we have different dietary requirements for measuring blood glucose.
There are currently two ways to test blood glucose, one is by drawing venous blood and the other is by pricking the finger with a needle and assaying the peripheral blood. Insulin secretion levels are influenced by a variety of factors, including time of day and diet. Therefore, different reference ranges of blood glucose exist at different points in time. We mostly choose different times to measure according to the needs of the patient’s condition.
Postprandial blood glucose mainly observes the secretion of insulin and blood glucose levels after the patient has eaten. It is the food that has a greater impact in this process. Water does not contain sugar, so drinking water does not interfere with postprandial glucose.
Pre-meal blood glucose, also known as fasting blood glucose, requires the experimenter to measure it when he or she is not eating or drinking when we are measuring the reference range; drinking water expands the body’s blood volume, so that the amount of blood glucose contained in each liter is diluted. Therefore, preprandial blood glucose requires conditions without eating or drinking to more accurately reflect true levels.
In summary, preprandial glucose measurement requires that no water be consumed, whereas postprandial glucose measurement does not require that no water be consumed.