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 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 to hopefully detect problems at an earlier stage.
- Monitoring is testing used to follow your condition over time or in response to treatment. Total protein may be measured in repeat tests at regular intervals if you 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 the different blood proteins in the liquid portion of blood (plasma or serum).
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 and carrying substances through the body.
Almost all of the other proteins in the blood are globulins, 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 calculating the number of globulins by subtracting albumin from total protein. It also allows for a calculation of the A/G 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 this 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 discomfort.
As a screening test, total protein and the A/G ratio may be part of a liver panel or comprehensive metabolic panel done during routine doctor visits if you have an elevated risk of developing kidney or liver disease, or a cancer such as multiple myeloma.
Diabetes, high blood pressure, or a family history of liver or kidney problems are risk factors frequently considered when determining whether screening is appropriate. Studies have not demonstrated that screening is beneficial if you don’t have 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 known to potentially impact the kidney or liver.
Finding a Total Protein and Albumin-to-Globulin Ratio Test
How can I get a total protein test?
A total protein test is typically performed after it has been prescribed by a doctor, although you can also order a protein test online. Doctor-ordered protein tests usually take a blood sample with a blood draw in a hospital, doctor’s office, or similar medical setting while at-home tests may use a urine sample to test protein levels.
Can I take the test at home?
Some at-home test kits include total protein and albumin. You can collect a blood sample at home with a fingerstick or provide a urine sample, but the sample must be mailed to a laboratory where the total protein can be measured. Some at-home protein tests take multiple samples over a 24-hour period, which can provide a more accurate assessment for the measurement than a random, single-point urine test.
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, if 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. Insurance often covers these charges if your doctor prescribes a total protein test. Still, contact your insurance company to find out if you are responsible for a deductible or copayments.
Taking a Total Protein and Albumin-to-Globulin Ratio Test
A total protein test requires a blood or urine sample for analysis. Most often, blood samples are 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 A/G ratio alone, you usually do not need to follow any special instructions before the test. But if you take a panel test with more measurements than total protein, you may be told to fast. This means avoiding all food and drinks other than water for 8 to 12 hours before the blood draw.
Some medications can affect the results of a total protein test. For that reason, 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
During 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 skin area near a vein will be cleaned with an antiseptic, and then a needle will be inserted into the vein to withdraw a vial of blood. After the needle is removed, the test is complete.
A blood draw does not usually cause 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.
With urine sample protein tests, you’ll need to urinate into a cup and return the sample to the lab for testing. Most tests will instruct you not to collect your sample the first time you urinate in the morning.
After the test
When your blood draw is over, you can usually return to your standard daily activities. If you had a fasting panel test, 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
Total protein test results are typically available a few business days after your blood draw or urine sample is sent to the lab. 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 and a normal 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 in your specific report. Reference ranges 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 infections and certain cancers affecting the immune system (for example, myeloma and certain lymphoma). High protein levels can also occur from dehydration and during pregnancy.
Abnormally low protein levels can have many causes, including several conditions affecting the liver or kidneys. Decreased total protein can also 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 A/G ratio may also be considered in the interpretation of your test. An A/G ratio can be high or low due to abnormal changes to albumin levels, globulins, or both.
A low A/G ratio has been associated with many illnesses, which may be related to inflammation or certain cancer such as myeloma. The A/G ratio can be decreased with short-term problems that cause inflammation, such as tissue trauma or infection, chronic inflammatory conditions, and nutritional problems.
For people with immune disorders, the A/G ratio may provide insight into how the condition affects the liver, gastrointestinal system, and nutrition.
Studies have suggested an association between a low A/G ratio and chronic kidney disease and potential ties between a low A/G ratio and worse health outcomes if you have certain types of cancer.
Because multiple factors can affect both albumin and globulins, more studies are needed to verify and better understand why a low A/G ratio may have these potential health implications.
Total protein test results and your A/G ratio should always be interpreted in discussion with your doctor. The test’s significance can only be properly understood by considering your specific context, including your medical history, present symptoms, overall health, and other 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 A/G 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 you suggest based on my total protein test?