The difference between peripheral blood and venous blood

Peripheral blood refers to finger blood and earlobe blood. Many friends often don’t know whether to draw venous blood or peripheral blood (finger blood) when they have a physical examination or various tests. The difference between peripheral blood and venous blood is that peripheral blood is easier to draw and the person having blood drawn will not feel particular pain, but blood cannot be drawn multiple times, while the opposite is true for venous blood. The specific differences are detailed below.

The human body's blood circulates through the heart and arteries, veins, and capillaries throughout the body. There are two main types of samples used for blood tests in hospitals, namely venous blood and peripheral blood.

Venous blood is generally drawn from the elbow vein (commonly known as: arm blood) with a syringe. The amount of blood drawn varies from a few milliliters to dozens of milliliters depending on the test items and the number of items. It is generally used in biochemical and immunological experiments such as blood sugar, blood lipids, liver and kidney function, immunoglobulins, thyroid function, and most special experiments.

Finger blood and earlobe blood are called peripheral blood, which is usually taken from the fingertips or earlobes. The amount of blood collected is small and is often used for simple and quick tests such as routine blood tests, blood type, and rapid blood sugar. However, many medical institutions now use venous blood for routine blood tests, which can obtain more accurate and stable results.

What is the difference between finger blood blood sugar and venous blood blood sugar? Finger blood contains capillary whole blood and tissue fluid, while venous blood is simple blood without tissue fluid.

Testing venous blood glucose generally requires the use of a biochemical analyzer, and hospitals generally use venous plasma for testing.

When hospitals use venous blood to test blood sugar, they usually separate the red blood cells from the venous blood and use the plasma to measure blood sugar.

Finger blood is capillary whole blood, including plasma and red blood cells.

Red blood cells contain less glucose than plasma, so the blood sugar level of whole blood from a fasting finger sample should be about 12% lower than the plasma blood sugar level of venous blood. Because blood sampling is often accompanied by exudation of tissue fluid, the blood sugar level of finger samples is more likely to be lower than the venous plasma blood sugar level.

However, after eating, the glucose absorbed by the human body first goes to the arteries, then returns to the veins after some of the glucose is consumed through peripheral metabolism in the capillaries. Therefore, at this time, the arterial blood sugar level is higher than the venous blood sugar level.

Capillaries are close to arteries, so capillary blood sugar is correspondingly higher than venous blood sugar after eating. However, this is exactly the opposite of the above-mentioned relationship that finger blood sugar is lower than venous plasma blood sugar due to red blood cells and tissue fluid. Therefore, after eating, these two factors offset each other, making capillary whole blood blood sugar and venous plasma blood sugar roughly the same.