• Also Known As:
  • Serum Protein
  • A/G Ratio Test
  • Formal Name:
  • Total Protein
  • Albumin to Globulin Ratio
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Test Quick Guide

A total protein test measures the sum of all types of proteins in the blood. Proteins are fundamental to the functioning of the body. The two main types of proteins found in the blood are albumin and globulins.

Measuring the total protein level as well as the ratio of albumin to globulin can help detect several kinds of health problems, including liver and kidney disease as well as nutritional deficiencies.

In many cases, total protein is included with other measurements using the same blood sample in a test like a liver panel or comprehensive metabolic panel. Whether tested alone or in a panel, total protein and the albumin-to-globulin ratio can be involved in the diagnosis, screening, and monitoring of a range of health conditions.

About the Test

Purpose of the test

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 many cases, the total protein measurement and A/G ratio are included as part of broader tests, such as the liver panel or comprehensive metabolic panel, that offer further information about possible health conditions.

In addition to the total protein level, testing can determine the ratio between types of proteins known as albumin and globulins. The albumin-to-globulin ratio, or A/G ratio, can also be used to look for signs of an underlying health issue.

This testing can be utilized as part of diagnosis, screening, and/or monitoring:

  • Diagnosis happens after you have symptoms and includes tests that work to determine what is causing those symptoms.
  • Screening involves tests that look for health problems before they have caused any symptoms. Panel tests including total protein, for example, may be part of routine checkups for people who have a higher risk of developing liver or kidney disease with the hope of detecting problems at an earlier stage.
  • Monitoring is testing that is used to follow a person’s condition over time or in response to treatment. Total protein may be measured in repeat tests at regular intervals in people who have known liver or kidney problems. It can also be part of panel tests to check liver and kidney health when taking medications that can affect these organs.

What does the test measure?

A total protein test measures the combined sum of all of the different proteins in the blood.

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 out of the blood and also carries substances through the body.

Almost all of the other proteins in the blood are globulins. Globulins are 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 a calculation of the number of globulins by subtracting albumin from total protein. It also allows for a calculation of the albumin-to-globulin ratio.

Total protein is often tested as part of a broader blood test. For example, the liver panel measures albumin, total protein, and a collection of enzymes that provide information about liver health.

When should I get a total protein test?

There are no strict guidelines for when a total protein test is performed. Its use depends on your specific circumstances, and in many cases, it is tested as part of a broader panel test.

For diagnosis, total protein may be measured if you have symptoms that could be caused by a liver or kidney problem. Examples of symptoms associated with liver or kidney disease include jaundice, urinary changes, fatigue, unexplained swelling, nausea, vomiting, and abdominal pain.

As a screening test, total protein and the A/G ratio may be part of a liver panel or comprehensive metabolic panel that is done during routine doctor visits for people who have an elevated risk of developing kidney or liver disease.

Diabetes, high blood pressure, or a family history of liver or kidney problems are risk factors that are frequently considered when determining whether screening is appropriate. Studies have not demonstrated that screening is beneficial in people without risk factors, but some doctors may include these tests in blood work done during normal checkups.

A total protein test can be utilized for monitoring liver or kidney health if you have already had an abnormal test result or have been previously diagnosed with an underlying illness. Testing can also help monitor for side effects of prescription drugs that are known to potentially impact the kidney or liver.

Finding a Total Protein and Albumin-to-Globulin Ratio Test

How to get tested

A total protein test is typically performed after it has been prescribed by a doctor. The blood sample is normally taken with a blood draw in a hospital, doctor’s office, or similar medical setting.

Can I take the test at home?

Some at-home test kits include total protein and albumin. WIth these kits, you can collect a blood sample at home with a fingerstick, but the sample must be mailed to a laboratory where the total protein can be measured.

How much does the test cost?

The cost of a total protein test may vary based on a number of factors including where the test is taken, whether other measurements are included in the test, and whether you have any type of health insurance.

Instead of one total cost, there may be separate bills for office visits, technician fees for the blood draw, and laboratory analysis. These charges are often covered by insurance if your doctor prescribes a total protein test, but you should contact your insurance company to find out if you are responsible for a deductible or copayments.

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Taking a Total Protein and Albumin-to-Globulin Ratio Test

A total protein test requires a blood sample for analysis, and most often that sample is drawn from a vein in your arm during a visit to a medical office.

Before the test

For a test of total protein and the albumin-globulin ratio alone, you usually do not need to follow any special instructions before the test. However, if you are taking a panel test with more measurements than total protein, you may be told to fast. This means avoiding all food and any drinks other than water for up to 12 hours before the blood draw.

Some medications can affect the results of a total protein test. For that reason, you should let your doctor know about any prescription drugs, over-the-counter medications, or dietary supplements that you regularly take. Your doctor can tell you whether you need to temporarily stop taking any of them before your test.

During the test

For the blood draw for a total protein test, a technician will tie an elastic band tightly around the upper part of your arm near your bicep. This increases blood flow lower in your arm, making it easier to take the blood sample.

The area of skin near a vein will be cleaned with an antiseptic, and then a needle will be inserted into the vein in order to withdraw a vial of blood. The needle will then be removed, and the test is complete.

A blood draw does not usually cause any serious or lasting problems, but you may notice some pain during the procedure and some soreness or bruising afterward. In total, the procedure is usually over in a few minutes. A bandage is usually put over the puncture site to stop bleeding once the test is over.

After the test

When your blood draw is over, you can usually return to your standard daily activities. If you had a panel test that required fasting, you may want to bring a snack to eat immediately after the test.

Total Protein and Albumin-to-Globulin Ratio Test Results

Receiving test results

The results from a total protein test are typically available a few business days after your blood draw. The test report may be provided electronically or sent by mail. Your doctor may also contact you by phone or email to provide or review the test results.

Interpreting test results

Total protein is measured in grams of protein per deciliter of blood (g/dL). You will find the total protein result on your test report along with a reference range for the laboratory that performed the test.

It is important to consider your total protein levels in relation to the reference range listed on your specific report. Ranges can vary based on the laboratory, so there is no universally accepted normal range for total protein.

The American Board of Internal Medicine lists the following reference ranges for a test of proteins in the blood:

  • Total proteins: 5.5 to 9.0 g/dL
  • Albumin: 3.5 to 5.5 g/dL
  • Globulins: 2.0 to 3.5 g/dL

When total protein levels are abnormally high, it can be related to conditions that cause chronic inflammation. Total protein can be elevated with some types of infections and certain cancers that affect the immune system. High protein levels can also occur from dehydration and during pregnancy.

Abnormally low protein levels can have many causes including several different conditions that affect the liver or kidneys. Decreased total protein can result from malnutrition and disorders that affect the gastrointestinal system and interfere with the normal absorption of nutrients. Other conditions, such as serious burns and internal bleeding, may also reduce total protein in the blood.

The albumin-to-globulin ratio may also be considered in the interpretation of your test. The A/G ratio can be high or low as a result of abnormal changes to levels of albumin, globulins or both.

A low A/G ratio has been associated with a number of illnesses, and this may be tied to inflammation. A/G ratio can be decreased with short-term problems that cause inflammation, such as tissue trauma or infection, as well as chronic inflammatory conditions and nutritional problems.

For people with immune disorders, the A/G ratio may provide insight into how the condition is affecting the liver, gastrointestinal system, and nutrition.

While research is still ongoing, some studies have found an association between a low A/G ratio and chronic kidney disease. Other research has found potential ties between a low A/G ratio and worse health outcomes in people with certain types of cancer. Because multiple factors can affect both albumin and globulins, more studies are needed to verify and better understand the underlying reasons for why a low A/G ratio may have these potential health implications.

The results of a total protein test and your A/G ratio should always be interpreted in discussion with your doctor. The significance of the test can only be properly understood by considering your specific context including your medical history, present symptoms, overall health, and other test results.

Do I need follow-up tests?

If you have an abnormal level of total protein or an irregular albumin-to-globulin ratio, it is likely that you will need follow-up tests. A total protein test alone typically cannot precisely identify an underlying problem, so other tests are usually necessary.

Follow-up tests can include more detailed measurement of blood proteins, other assessments of liver and kidney health, imaging tests, or any other exams that your doctor believes may be beneficial based on your symptoms, health history, and test results.

Questions for your doctor about test results

To learn the most about your total protein test and what the results may mean, you can discuss some or all of the following questions with your doctor:

  • What was my total protein level? Was my albumin-to-globulin ratio calculated?
  • Were any other measurements taken with my blood sample?
  • Were my results normal or abnormal?
  • If my total protein or A/G ratio was abnormal, what are the possible explanations? Which explanation do you think is most likely and why?
  • Do you recommend repeating the total protein test?
  • Are there any other follow-up tests that you suggest based on my total protein test?

Related Tests

A number of blood and urine tests are used to measure proteins. The following sections help explain how these related tests are distinct from a total protein and A/G ratio test.

How is a total protein test different from a serum protein electrophoresis test?

There are different methods for testing the proteins in the blood. A total protein test measures the amount of all types of proteins. In addition, by measuring albumin specifically, the albumin-to-globulin ratio can be calculated with this test.

Another protein test is called serum protein electrophoresis. Also known as SPE or SPEP, this test measures more types of proteins, including different kinds of globulins. Because the levels of specific globulins are related to immune function, serum protein electrophoresis is frequently used to detect conditions affecting the immune system.

How is a total protein test different from a urine protein test?

A total protein test uses a blood sample, which makes it distinct from a urine protein test.

In addition, the interpretation of these tests is different based on the expected amount of protein in blood and urine. It is normal and expected for proteins to be found in the blood. On the other hand, very little protein is typically found in the urine because the kidneys keep it from passing from blood to urine.

How is a total protein and albumin-globulin ratio test different from an albumin blood test?

A total protein test counts more types of protein than an albumin blood test. Albumin is one type of protein, so it is included in a total protein measurement. But total protein also counts globulins, another kind of protein.

In most cases, a total protein test involves a specific measurement of albumin, which allows the albumin-to-globulin ratio to be calculated.

How is a total protein test different from a liver panel or comprehensive metabolic panel?

A panel test involves multiple different measurements taken using the same sample. Total protein is one of the test components in the liver panel and in the comprehensive metabolic panel.

A liver panel tests total protein, albumin, and a series of enzymes that provide information about liver health. A comprehensive metabolic panel includes all of the components of the liver panel and also assesses the body’s energy use, electrolytes, and kidney function.

Sources

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A.D.A.M. Medical Encyclopedia. Comprehensive metabolic panel. Updated January 26, 2019. Accessed June 30, 2021. https://medlineplus.gov/ency/article/003468.htm

A.D.A.M. Medical Encyclopedia. Total protein. Updated April 29, 2019. Accessed June 30, 2021. https://medlineplus.gov/ency/article/003483.htm

A.D.A.M. Medical Encyclopedia. Protein electrophoresis – serum. Updated June 9, 2021. Accessed June 30, 2021. https://medlineplus.gov/ency/article/003540.htm

American Board of Internal Medicine. ABIM laboratory test reference ranges. Updated January 2021. Accessed June 30, 2021. https://www.abim.org/Media/bfijryql/laboratory-reference-ranges.pdf

He J, Pan H, Liang W, et al. Prognostic effect of albumin-to-globulin ratio in patients with solid tumors: A systematic review and meta-analysis. J Cancer. 2017;8(19):4002-4010. Published 2017 Oct 23. doi:10.7150/jca.21141

Gounden V, Vashisht R, Jialal I. Hypoalbuminemia. In: StatPearls. Updated April 1, 2021. Accessed June 30, 2021. https://www.ncbi.nlm.nih.gov/books/NBK526080/

LePelusa A, Kaushik R. Physiology, proteins. In: StatPearls. Updated December 5, 2020. Accessed June 30, 2021. https://www.ncbi.nlm.nih.gov/books/NBK555990/

MedlinePlus: National Library of Medicine. Albumin blood test. Updated July 30, 2020. Accessed June 30, 2021. https://medlineplus.gov/lab-tests/albumin-blood-test/

MedlinePlus: National Library of Medicine. Globulin test. Updated July 31, 2020. Accessed June 30, 2021. https://medlineplus.gov/lab-tests/globulin-test/

MedlinePlus: National Library of Medicine. Protein in urine. Updated July 31, 2020. Accessed June 30, 2021. https://medlineplus.gov/lab-tests/protein-in-urine/

MedlinePlus: National Library of Medicine. Comprehensive metabolic panel (CMP). Updated March 2, 2021. Accessed June 30, 2021. https://medlineplus.gov/lab-tests/comprehensive-metabolic-panel-cmp/

MedlinePlus: National Library of Medicine. Liver function tests. Updated March 4, 2021. Accessed June 30, 2021. https://medlineplus.gov/lab-tests/liver-function-tests/

National Health Service (UK). Total protein test. Updated September 21, 2018. Accessed July 1, 2021. https://www.nhs.uk/conditions/total-protein-test/

Park J, Kim HJ, Kim J, Choi YB, Shin YS, Lee MJ. Predictive value of serum albumin-to-globulin ratio for incident chronic kidney disease: A 12-year community-based prospective study. PLoS One. 2020;15(9):e0238421. Published 2020 Sep 2. doi:10.1371/journal.pone.0238421

Rezaei N, Mohammadinejad P, Zeinoddini A, Abolhassan H. Gastrointestinal manifestations in primary immunodeficiency. In: Notarangelo LD, ed. UpToDate. Updated January 22, 2021. Accessed June 30, 2021. https://www.uptodate.com/contents/gastrointestinal-manifestations-in-primary-immunodeficiency

Vavricka SR, Burri E, Beglinger C, Degen L, Manz M. Serum protein electrophoresis: an underused but very useful test. Digestion. 2009;79(4):203-210. doi:10.1159/000212077

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