The purpose of a total protein test is to check the levels of proteins in the blood. Too much or too little protein can reflect conditions including liver or kidney disease, infection, inflammation, malnutrition, and cancer. In addition to the total protein level, testing can determine the ratio between types of proteins known as albumin and globulins. The A/G ratio can also be used to look for signs of an underlying health issue.

Proteins are vital to the functioning of virtually all parts of the body. The most common protein in the blood is albumin, which prevents fluid from leaking and carrying substances through the body. Almost all of the other proteins in the blood are globulins, formed by the immune system and by the liver. There are several kinds of globulins, but a basic total protein test usually will not measure the amounts of each specific type. A blood test of total proteins will often directly measure albumin. This allows for calculating the number of globulins by subtracting albumin from total protein. It also allows for a calculation of the A/G ratio.

When should I get this test?
As a screening test, total protein and the A/G ratio may be part of a liver panel or comprehensive metabolic panel done during routine doctor visits if you have an elevated risk of developing kidney or liver disease, or a cancer such as multiple myeloma. Diabetes, high blood pressure, or a family history of liver or kidney problems are risk factors frequently considered when determining whether screening is appropriate. Studies have not demonstrated that screening is beneficial if you don’t have risk factors, but some doctors may include these tests in blood work done during normal check-ups