Total Protein

Proteins are large, complex molecules that are vital for all cells and tissues of the body. They are produced in different places throughout the body and circulate in the blood.

The blood plasma contains hundreds of different proteins. By measuring the concentration of these proteins, one can obtain information about the states of various organ systems.

Interpret now "Complete Blood Count (CBC)"
Interpret now "Urinalysis (UA)"

The total protein is an indicator of the protein metabolism of the body, which reflects the total content of all proteins in the blood serum. Blood consists of a liquid part (plasma) and a solid part (the formed elements) that includes red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Serum is the liquid part of the blood that remains after clotting of the plasma, in other words, after the removal of fibrinogen – the protein responsible for blood clotting. Therefore, the protein in the blood plasma is 2-4 g/L higher than in the serum due to the presence of fibrinogen.

A total protein test is often included in the "Liver Function Tests". Total protein test may also be done along with other tests if there are symptoms that indicate kidney disorder, or if there is edema.

The total protein test provides information about the patient's general status. More clinically useful data can be obtained by studying the basic protein fractions. Proteins of blood serum can be divided into two main groups (fractions) – albumin and globulin. Serum also contains other proteins, but none contributes more than 5% of the total, and most much less.

Albumin is synthesized in the liver and makes up about 55% of all blood proteins. It plays an important role in preventing leakage of fluid from the blood vessels in the tissue. Albumin also helps carry bilirubin, hormones, vitamins, and medicines through the blood.

Globulins are a group of proteins that include enzymes, antibodies, and more than 500 other proteins. Most globulins are synthesized in the liver, and others are made by the immune system. Globulins participate in immune reactions, help fight infections, and transfer nutrients.

Normal Total Protein Levels

The normal level of total protein is about 6-8 g/dL (60-83 g/L). Albumin makes up 3.5 to 5.0 g/dl (35-50 g/L), the rest are globulins. These values may vary depending on the laboratory, gender, age, and other factors. To interpret the lab test results one should use the reference range of the laboratory in which the test was performed.

The total protein level in the blood can be elevated (hyperproteinemia), decreased (hypoproteinemia), or normal (normoproteinemia). Measuring the concentration of total protein in the blood, as well as the ratio of its fractions is an important diagnostic parameter for many diseases.

Changes in the total protein level can be relative and absolute. The relative increase/decrease in total protein level is a result of an increase/decrease in the amount of water in the bloodstream – that is, when blood is thin or thick. The absolute nature of the changes is a result of fluctuations in the level of protein in the blood.

High Total Protein Levels

High total protein in the blood is not a specific disease or condition, but it may indicate some problems in the body. High total protein rarely causes symptoms on its own. It is often found in a blood test made to evaluate some other problem or symptom.

If the result of a total protein test lies outside the laboratory reference ranges, it is necessary to make additional tests to determine which proteins are elevated or lowered.

Total protein levels in the blood may be high due to dehydration. Drinking enough water before the test will help to get a more accurate result.

Low Total Protein Levels

A low level of total protein in the blood may indicate a kidney disorder, a liver disorder, or a disease in which the protein is not digested or absorbed properly.

Total Protein Levels During Pregnancy

Low total protein in the blood during pregnancy can occur due to an increase in the volume of the liquid part of the blood. High protein levels during pregnancy can be an early sign of pre-eclampsia or another disease.

Comprehensive Metabolic Panel (CMP) Interpretation