Serum total protein, also called plasma total protein or total protein, is a biochemical test for measuring the total amount of protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 in blood plasma

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

 or serum

Blood serum

In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...

.

Protein in the plasma is made up of albumin

Serum albumin

Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...

 and globulin

Globulin

Globulin is one of the three types of serum proteins, the others being albumin and fibrinogen. Some globulins are produced in the liver, while others are made by the immune system. The term globulin encompasses a heterogeneous group of proteins with typical high molecular weight, and both...

. The globulin in turn is made up of α1, α2, β

Beta globulins

Beta globulins are a group of globular proteins in plasma thatare more mobile in alkaline or electrically charged solutions than gamma globulins, but less mobile than alpha globulins. Beta globin is on chromosome 11.Examples of beta globulins include:...

, and γ globulins. These fractions can be quantitated using protein electrophoresis

Protein electrophoresis

Protein electrophoresis is a method for analysing the proteins in a fluid or an extract. The electrophoresis may be performed with a small volume of sample in a number of alternative ways with or without a supporting medium: SDS polyacrylamide gel electrophoresis Protein electrophoresis is a method...

, but the total protein test is a faster and cheaper test that estimates the total of all fractions together.