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Patient Test Information

Total Protein, Albumin-Globulin (A/G) Ratio

  • Why Get Tested?

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

    When To Get Tested?

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

    Sample Required?

    A blood sample drawn from a vein or by fingerstick or, in the case of newborns, by heelstick

    Test Preparation Needed?

    None

  • 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 amount of protein in your blood.

    Two classes of proteins are found in the blood, albumin and globulin.

    • Albumin is made by the liver and makes up about 60% of the total protein. Albumin keeps fluid from leaking out of blood vessels, nourishes tissues, and transports hormones, vitamins, drugs, and substances like calcium throughout the body.
    • Globulins make up the remaining 40% of proteins in the blood. The globulins are a varied group of proteins, some produced by the liver and some by the immune system. They help fight infection and transport nutrients.

    The test also compares the amount of albumin with globulin and calculates what is called the A/G ratio. A change in this ratio can provide your healthcare practitioner with a clue as to the cause of the change in protein levels.

    Total protein levels in the blood may increase or decrease, to a greater or lesser degree, with various conditions.

    Total protein levels may decrease in conditions that:

    • Interfere with production of albumin or globulin proteins, such as malnutrition or severe liver disease
    • Increase the breakdown or loss of protein, such as kidney disease (nephrotic syndrome)
    • Increase or expand the volume of plasma, the liquid part of blood (diluting the blood), such as congestive heart failure

    Total protein levels may increase with conditions that cause:

    • Abnormally high production of protein (e.g., inflammatory disorders, multiple myeloma)
    • Dehydration
  • How is the test used?

    Total protein and albumin tests may be used, along with other tests included in panels such as a comprehensive metabolic panel (CMP), to help evaluate your overall health status.

    These tests may also be used to help diagnose diseases and to monitor conditions or treatments. Total protein levels can be affected by many different diseases and disorders. For example, a total protein test may be used to help diagnose kidney disease or as part of a liver panel to help detect liver disease.

    Results may indicate the need further testing. If total protein is abnormal, your healthcare practitioner may recommend follow-up tests, such as protein electrophoresis and quantitative immunoglobulins.

    Some laboratories report total protein, albumin, and also the calculated ratio of albumin to globulins, the A/G ratio. 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 you have a routine health checkup.

    Total protein may also be ordered if you have signs and symptoms, such as:

    • Unexplained weight loss
    • Fatigue
    • Swelling caused by extra fluid in your tissue (edema)
    • Symptoms of liver disease, a kidney disease, or bone marrow disorder

    What does the test result mean?

    Results of a total protein test are evaluated along with those from other tests of the CMP. If results are abnormal, further tests are required to identify which protein is high or low before your healthcare practitioner can make a diagnosis.

    Some examples of conditions that cause low total protein include:

    • Liver disorder
    • Kidney disorder
    • A disorder in which protein is not digested or absorbed properly
    • Malnutrition
    • Malabsorption such as celiac disease or inflammatory bowel disease (IBD)

    Some examples of conditions that cause high total protein include:

    • Chronic inflammation or infections such as viral hepatitis or HIV
    • Bone marrow disorders such as multiple myeloma

    Low A/G ratio may be caused by:

    • Overproduction of globulins, such as seen in multiple myeloma or autoimmune diseases
    • Underproduction of albumin, such as may occur with cirrhosis
    • Selective loss of albumin from the circulation, as may occur with kidney disease (nephrotic syndrome)

    High A/G ratio may be caused by:

    • Underproduction of immunoglobulins as happens in some genetic deficiencies
    • Leukemias

    Will a high protein diet raise my total protein level?

    No, eating more protein will not increase your total protein test result.

    What type of nutrition is recommended for optimal protein levels?

    There is no specific diet. 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 a group of proteins in the blood, some produced by the liver and some by the immune system. They help fight infection and transport nutrients. There are four main types: alpha 1, alpha 2, beta, and gamma. They are measured using different tests:

    • Total protein test—measures albumin and globulin
    • Serum protein electrophoresis—can be used to measure the different groups of globulin proteins

    Can protein be measured in samples other than blood?

    Yes, a test for protein can be performed on many different types of body fluids. Proteins are also measured in urine. The purpose of urine testing and the meaning of results are different than from blood. See the articles on Body Fluid Testing, Urine Protein, and Urinalysis for more information.

    Is there anything else I should know?

    Many medications may affect total protein levels, including estrogens, steroids, and oral contraceptives. Tell your healthcare practitioner all the prescription or over-the-counter medications, supplements, or illicit substances you may be taking.

  • View Sources

    Sources Used in Current Review

    2019 review performed by Marina Marinkovic, PhD, Principal Scientist, Nova Biomedical.

    What to know about the protein test and results. MedicalNewsToday. Available online at https://www.medicalnewstoday.com/articles/325320.php. Accessed 8/12/19.

    What Is a Total Serum Protein Test? WebMed. Available online at https://www.webmd.com/a-to-z-guides/what-is-a-total-serum-protein-test#2. Accessed 8/12/19.

    Total Protein and A/G Ratio. University of Rochester Medical Center. Available online at https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=total_protein_ag_ratio. Accessed 8/12/19.

    Globulin Test. MedlinePlus. Available online at https://medlineplus.gov/lab-tests/globulin-test/. Accessed 8/12/19.

    Sources Used in Previous Reviews

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    (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.

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