What is the Difference Between Plasma and Serum?

Plasma and serum are both derived from the liquid portion of blood, but they have distinct differences:

• Plasma is the liquid that remains when clotting is prevented with the addition of an anticoagulant. It is composed of serum and clotting factors, such as fibrinogen and blood clotting factors. Plasma is obtained in the upper layer during centrifugation and is used in blood transfusions and certain research applications.
• Serum is the liquid that remains after the blood has clotted. It lacks clotting factors and is obtained by centrifuging blood and removing the fibrin clots, blood cells, and related coagulation factors. Serum is often used in research and diagnostic tests, as it helps in the diagnosis of diseases such as blood pressure, sugar, and cholesterol.

Some key differences between plasma and serum include:

1. Clotting factors: Plasma contains clotting factors, while serum does not.
2. Preparation: Plasma is obtained by adding an anticoagulant to prevent clotting, while serum is obtained by allowing blood to clot and then removing the clots.
3. Research applications: Serum is more widely used in research, as it removes unwanted red blood cells more efficiently, generating more volume per unit of blood. Plasma, on the other hand, is preferred when studying blood clotting or when blood is being used for transfusion.
4. Lipoprotein levels: Lipoprotein levels are often lower in plasma than serum, but lipoprotein composition in plasma and serum is typically consistent within the same sample.

It is essential to use the same collection method (plasma or serum) within a single study to ensure consistent results and to enable comparison between different studies.

Comparative Table: Plasma vs Serum

Here is a table summarizing the differences between plasma and serum:

Plasma is obtained by centrifuging blood with anticoagulants, which prevents clotting and allows for the separation of plasma from other blood components. Serum, on the other hand, is obtained by centrifuging clotted blood, which separates the liquid portion from the clot. Both plasma and serum are used for diagnostic purposes, but they have different compositions and uses in disease diagnosis.