Known as: A/G ratio
Also known as: TP, albumin/globulin ratio
Name: Total protein; albumin/globulin ratio
Related tests: Albumin, Liver panel
Why is the test done?
To assess nutritional status or to evaluate certain liver and kidney disorders, as well as other conditions.
When is the test done?
If you have unexplained weight loss or tiredness, or if the doctor thinks you have symptoms that may be linked to liver or kidney disorders.
Sample required?
A blood sample taken from a vein in the arm or from a fingertip (adults and children), or by heel prick (newborns).
What is being tested?
The total protein test is a rough measurement of the protein content of blood plasma. Proteins are the basic building blocks of every cell and tissue; they are important for the body’s growth and health. Total protein measures the combined amount of two classes of protein, albumin and globulin. Albumin carries many small molecules, but its main role is to draw fluid back from the interstitial spaces, while the globulins include enzymes, antibodies and more than 500 other proteins. The albumin/globulin ratio (A/G ratio) is calculated from the directly measured values of total protein and albumin. It represents the relative amounts of albumin and globulins.
How is the sample collected?
A blood sample taken from a vein in the arm or from a fingertip (adults and children), or by heel prick (newborns).
How is the test used?
When is it requested?
What do the test results mean?
Is there anything else to know?
How is the test used?
Total protein can reflect nutritional status, kidney disease, liver disease and many other conditions. If total protein is abnormal, various tests can be carried out to identify which protein fraction is altered and so make a specific diagnosis.
When is it requested?
It is ordered to obtain general information about nutritional status, for example after sudden weight loss. It is also ordered, together with other tests, when symptoms suggest liver or kidney disorders, or to investigate the cause of fluid retention in the tissues.
What do the test results mean?
A low total protein concentration may suggest a liver disorder, a kidney disorder, or a disorder in which protein is not digested or absorbed properly. Some laboratories report the ratio of albumin to globulins, known as the A/G ratio. Normally there is slightly more albumin, so the A/G ratio is just above 1.
Because diseases affect albumin and globulins differently, the ratio can suggest the cause of these changes. A low A/G ratio may reflect overproduction of globulins (as in multiple myeloma or autoimmune diseases), underproduction of albumin (as in cirrhosis) or selective loss of albumin (as in nephrotic syndrome). A high A/G ratio suggests underproduction of immunoglobulins (as seen in some genetic deficiencies and some leukaemias). More specific tests, such as albumin, liver enzymes and protein electrophoresis, may be carried out to make an accurate diagnosis.
Is there anything else to know?
Leaving a tourniquet on for a long time can cause a high protein concentration in the sample. This means the result may be falsely high (higher than in the bloodstream). Medicines that can lower circulating protein levels include oestrogens and oral contraceptives.
1. Can the test be done at home?
2. Can a high-protein diet raise total protein?
3. What kind of diet is recommended for an optimal protein level?
1. Can the test be done at home?
No, there are no home tests on the market.
2. Can a high-protein diet raise total protein?
No, dietary protein intake does not change the test result.
3. What kind of diet is recommended for an optimal protein level?
A well-balanced diet following the recommendations of the United States Department of Agriculture, as described in the Food Pyramid.