Serum total protein, also called plasma total protein or total protein, is a biochemical test for measuring the total amount of protein in blood plasma or serum.
Protein in the plasma is made up of albumin and globulin. The globulin in turn is made up of α1, α2, β, and γ globulins. These fractions can be quantitated using protein electrophoresis, but the total protein test is a faster and cheaper test that estimates the total of all fractions together. The traditional method for measuring total protein uses the biuret reagent, but other chemical methods such as Kjeldahl method, dye-binding and refractometry are now available. The measurement is usually performed on automated analysers along with other laboratory tests.
The reference range for total protein is typically 60-80g/L. (It is also sometimes reported as "6.0-8.0g/dl"), but this may vary depending on the method of analysis.