Also Known As
TP
Albumin/Globulin Ratio
A/G Ratio
Formal Name
Total Protein; Albumin to Globulin Ratio
This article was last reviewed on
This article waslast modified on
January 15, 2018.
At a Glance
Why Get Tested?

As part of a general health checkup, to determine your nutritional status or to screen for and help diagnose certain liver and kidney disorders as well as other diseases

When To Get Tested?

When you have a routine physical exam or when you experience unexpected weight loss or fatigue, or when a healthcare practitioner thinks that you have symptoms of a liver or kidney disorder

Sample Required?

A blood sample drawn from a vein in your arm or by fingerstick (adults and children) or heelstick (newborns)

Test Preparation Needed?

None

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

For more information, please read the article Reference Ranges and What They Mean.

What is being tested?

Proteins are important building blocks of all cells and tissues; they are important for body growth, development, and health. They form the structural part of most organs and make up enzymes and hormones that regulate body functions. This test measures the total amount of the various types of proteins in the liquid (serum or plasma) portion of the blood.

Two classes of proteins are found in the blood, albumin and globulin. Albumin makes up about 60% of the total protein. Produced by the liver, albumin serves a variety of functions including as a carrier protein for many small molecules and ions, as a source of amino acids for tissue metabolism, and as the principle component involved in maintaining osmotic pressure (preventing fluid from leaking out of blood vessels).

The remaining 40% of proteins in the plasma are referred to as globulins. The globulin proteins are a varied group. They include enzymes, antibodies, hormones, carrier proteins, and numerous other types of proteins.

The level of total protein in the blood is normally a relatively stable value, reflecting a balance in loss of old protein molecules and production of new protein molecules.

Total protein may decrease in conditions:

Total protein may increase with conditions that cause:

Some laboratories report total protein, albumin, and the calculated ratio of albumin to globulins, termed the A/G ratio. The A/G ratio is calculated from measured total protein, measured albumin, and calculated globulin (total protein - albumin).

Normally, there is a little more albumin than globulins, giving a normal A/G ratio of slightly over 1. The A/G ratio may change whenever the proportions of albumin and other proteins shift (increase or decrease) in relationship to each other. Because disease states affect the relative amounts of albumin and globulin, the A/G ratio may provide a clue as to the cause of the change in protein levels.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm or by a fingerstick (for children and adults) or heelstick (for newborns).

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

Accordion Title
Common Questions
  • How is it used?

    Total protein and albumin tests are routinely included in the panels of tests performed as part of a health examination, such as a comprehensive metabolic panel (CMP), so they are frequently used to help evaluate a person's overall health status.

    Additionally, since total protein can be low, increased, or the component globulin proteins altered with many different diseases and disorders, total protein and albumin tests may be ordered in a variety of settings to help diagnose disease, to monitor changes in health status, and as a screen that may indicate the need for various follow-up tests.

    (For more information about proteins in the blood, see the "What is being tested?" section.)

    Total protein measurements can reflect nutritional status and may be used to screen for and help diagnose kidney disease or liver disease, for example. Sometimes conditions are detected with routine testing before symptoms appear. If total protein is abnormal, further testing must be performed to identify which specific protein is abnormally low or high so that a specific diagnosis can be made. Some examples of follow-up tests include protein electrophoresis and quantitative immunoglobulins.

    Some laboratories report total protein, albumin, and the calculated ratio of albumin to globulins, termed the A/G ratio. The A/G ratio is calculated from measured total protein, measured albumin, and calculated globulin (total protein - albumin). Because disease states affect the relative amounts of albumin and globulin, the A/G ratio may provide a clue as to the cause of the change in protein levels.

  • When is it ordered?

    A total protein test is frequently ordered as part of a comprehensive metabolic panel (CMP) when an individual undergoes a routine health checkup. Total protein may also be ordered to provide general information about a person's nutritional status, such as when someone has undergone a recent, unexplained weight loss. It can be ordered along with several other tests to provide information when someone has symptoms that suggest a liver, kidney, or bone marrow disorder, or to investigate the cause of abnormal pooling of fluid in tissue (edema).

  • What does the test result mean?

    Results of a total protein test are usually considered along with those from other tests of the CMP and will give the healthcare practitioner information on a person's general health status with regard to nutrition and/or conditions involving major organs, such as the kidney and liver. However, if results are abnormal, further testing is usually required to help diagnose the disease affecting protein levels in the blood.

    Following an abnormal total protein result and depending on the suspected cause, more specific tests are typically performed to make an accurate diagnosis. Some examples include liver enzyme tests, renal panel, serum protein electrophoresis, or tests for celiac disease or IBD.

  • Is there anything else I should know?

    Prolonged application of a tourniquet during blood collection can result in a blood sample with a falsely elevated total protein (higher than the actual concentration in the circulation).

    Drugs that may decrease protein levels include estrogens and oral contraceptives.

  • Will a high protein diet raise my total protein level?
    No, increasing your intake of protein will not increase your total protein test result.
  • What type of nutrition is recommended for optimal protein levels?

    A well-balanced diet that follows the recommendations of the United States Department of Agriculture is summarized by the USDA Choose My Plate.

  • What are globulin proteins and how are they measured in blood?

    Globulins are all the proteins in the blood other than albumin, and this group is comprised of hundreds of different types. These proteins are larger than albumin and are divided into alpha, beta and gamma globulins.

    A protein electrophoresis test can be used to quantify the different groups of globulin proteins (see the article on Protein Electrophoresis and the table on Protein Groups). An immunofixation electrophoresis test can measure the different types of immunoglobulins (e.g., IgG, IgM, IgA) as can a quantitative immunoglobulins test.

    Some globulin proteins can be measured directly using specific tests for the protein of interest. The tests are most valuable in instances where a specific protein is associated with a disease or condition. The specific protein tests may be ordered to provide information to the healthcare practitioner when particular signs and symptoms are present that suggest one of these diseases or conditions. A few examples of proteins associated with specific conditions are C-reactive protein (inflammation), fibrinogen (clotting disorders), ferritin (iron deficiency), and ceruloplasmin (Wilson disease).

  • Can protein be measured in samples other than blood?

    Yes, a test for protein can be performed on many different types of body fluids. The purpose for testing and the meaning of results vary. For more details, see the article on Body Fluid Analysis and select the link for the fluid of interest.

View Sources

Sources Used in Current Review

(© 1995–2016).Protein, Total, Serum. Mayo Clinic Mayo Medical Laboratories. [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/8520. Accessed 3/23/16.

Bertholf, R. (2014). Proteins and Albumin. Medscape Multispecialty from Lab Med. 2014;45(1):e25-e41. [On-line information]. Available online at http://www.medscape.com/viewarticle/823421_6. Accessed 3/23/16.

Shah, D. and Seiter, K. (2016 February 5 Updated). Multiple Myeloma. Medscape Drugs and Diseases. [On-line information]. Available online at http://emedicine.medscape.com/article/204369-overview#showall. Accessed 3/23/16.

Delgado, J. (2015 December Updated). Proteins. ARUP Consult [On-line information]. Available online at https://arupconsult.com/content/proteins. Accessed 3/23/16.

Martin, L. (2015 May 3 Updated). Total protein. MedlinePlus Medical Encyclopedia [On-line information]. Available online at https://www.nlm.nih.gov/medlineplus/ency/article/003483.htm. Accessed 3/23/16.

Durani, Y. (2014 August Reviewed). Hepatic (Liver) Function Panel. TeensHealth from Nemours [On-line information]. Available online at http://kidshealth.org/en/teens/test-liver-function.html. Accessed 3/23/16.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pp 543-546.

(May 17, 2007) Van Voorhees B. MedlinePlus Medical Encyclopedia. Total Protein. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003483.htm. Accessed April 2009.

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson RA and Pincus MR, eds. Philadelphia: 2007, Pp 231-236.

(November 3, 2007) Mayo Clinic: High protein in blood: What causes it? Available online at http://www.mayoclinic.com/health/protein-in-blood/AN01204. Accessed April 2009.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry. AACC Press, Washington, DC Pp 200, 206.

Dugdale, D. (Updated 2011 May 30). Total protein. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003483.htm. Accessed February 2013.

(© 1995–2013). Protein, Total, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8520. Accessed February 2013.

Alvaran Tuazon, S. and Scarpaci, A. (Updated 2012 May 11). Serum Protein Electrophoresis. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2087113-overview#showall. Accessed February 2013.

Gersten, T. (Updated 2012 February 8). Protein electrophoresis – serum. MedlinePlus Medical Encyclopedia [On-line information]. Available online at [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003540.htm. Accessed February 2013.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 799-804.

Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 233-246.

Ask a Laboratory Scientist

lab scientist

Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, the American Society for Clinical Laboratory Science (ASCLS). Click on the Contact a Scientist button below to be re-directed to the ASCLS site to complete a request form. If your question relates to this web site and not to a specific lab test, please submit it via our Contact Us page instead. Thank you.

Contact a Scientist