Confused about total protein, albumin, globulin, or the A/G ratio? Unsure if your results are normal and what the values mean? Read on to understand the total protein test, why your levels are low or high, and what you can do about them.
What is Total Protein?
Proteins are one of the building blocks of every cell. They also play an important role in many biological processes. They are essential for growth and development, nutrient and hormone transport, and immune function [1].
Normally, albumin makes up for slightly more than half of the proteins in the blood (serum, the liquid part of the blood), and the remainder of the protein count are the globulins [2].
Albumin
Albumin is produced in the liver. It helps transport hormones, bilirubin, metals, vitamins, and drugs. It also helps with fat metabolism and attracts fluids, preventing them from leaking out of blood vessels [2].
Globulins
The globulin proteins are a mixture of enzymes, antibodies, carriers, and other proteins. Most of them are made in the liver, although antibodies are produced by some types of white blood cells. Globulins are often raised due to increased antibody (immunoglobulin) production [2].
The A/G Ratio
The A/G ratio measures the relative ratio of albumin to globulin. This ratio can provide important clues about what may be wrong with your health when total protein levels are abnormal. Normally, albumin levels are only slightly higher than globulin, which gives an A/G ratio slightly over 1 [2].
A low A/G ratio may indicate viral infections, liver and kidney disease, or autoimmune disorders. These diseases increase globulin and decrease albumin thus lowering the A/G ratio [3].
A high A/G ratio may indicate diseases that make the body produce less globulin, such as genetic disorders or may result from the use of immunosuppressive drugs [2, 3].
Total Protein Test
This test measures albumin and total globulin levels in your blood. A healthcare professional will collect a blood sample from your vein and send it to a lab for analysis. The test is normally ordered as part of a comprehensive metabolic panel (CMP).
Why is the Test Performed?
The total protein test is often used to check liver or kidney disease. Your doctor may order the total protein test if you have symptoms of malnutrition or of liver or kidney dysfunction, such as [2, 4, 5]:
- Jaundice
- Nausea and vomiting
- Itching
- Fatigue
- Fluid buildup in the abdomen, feet, and legs
- Loss of appetite
- Weight loss
- Spider-like blood vessels on the skin
How to Prepare for the Test
Dehydration may affect the test, so make sure you drink enough water before heading to the doctor’s office. Also, talk with your doctor to make sure you are not taking any medications that may interfere with the test. Potentially troublesome drugs include [6]:
- Anabolic steroids and hormones (androgens, estrogens, progesterone, growth hormone)
- Corticosteroids
- Insulin
Normal Range
The normal ranges for adults can vary slightly between labs, but they are generally about 6.0 to 8.3 g/dL (60 to 83 g/L) [7, 8].
In newborns, total protein is lower: 4.6 to 7.0 g/dL is normal. Total protein increases slowly during the first three years of life, after which values are similar to adults [9].
Low Total Protein Levels
Causes
Causes shown here are commonly associated with low protein levels. Work with your doctor or another health care professional to get an accurate diagnosis.
A result that’s lower than normal, doesn’t necessarily mean that you have a health condition needing treatment. Your doctor will interpret your protein result, taking into account your medical history, symptoms, and other test results.
Possible causes of low protein levels include:
- Malnutrition, or a lack of nutrients in the diet [2]
- Gut disorders, such as celiac disease and inflammatory bowel disease (IBD), which can impair protein absorption [2, 10, 11]
- Severe liver disease [2]
- Kidney disease [2]
- Heart failure [12]
- Severe burns [2]
- Inborn immune deficiencies [2]
Increasing Total Protein Levels
The most important thing is to work with your doctor to find out what’s causing your low protein levels and to treat any underlying conditions. Your doctor may look at other tests such as albumin and globulin to figure out which one is decreasing your protein levels.
In addition, make sure you are eating a balanced, nutritious diet. That will prevent your protein levels from becoming too low [2].
High Total Protein Levels
Causes
Causes shown here are commonly associated with high protein levels. Work with your doctor or another health care professional to get an accurate diagnosis.
A result that’s higher than normal, doesn’t necessarily mean that you have a health condition needing treatment. Your doctor will interpret your protein result, taking into account your medical history, symptoms, and other test results.
Causes of high total protein levels include:
- Dehydration [2, 13]
- Viral infections [3]
- Autoimmune disorders [3]
- Chronic inflammation [3]
- Bone marrow disorders, such as multiple myeloma [2]
Decreasing Total Protein Levels
The most important thing is to work with your doctor to find out what’s causing your high protein levels and to treat any underlying conditions, such as infections or inflammation! Your doctor will likely run further tests.
Make sure you are drinking enough water to prevent dehydration [2, 13]. Also, limit your alcohol consumption: alcohol is a diuretic that causes your body to lose water, which can result in dehydration [14].
Remember, dietary proteins can’t increase your blood proteins. Don’t skimp on proteins and make sure your diet is well balanced.
Takeaway
The total protein test measures your albumin and total globulin levels in your blood. It is often used to check for poor nutrition status and liver or kidney disease.
The albumin portion makes up for slightly more than half of serum proteins, and the rest of the protein count is the total globulins.
If the ratio of albumin to globulin is unusually low, it may indicate viral infections, myeloma, liver and kidney disease, or autoimmune disorders. If the ratio is unusually high, it may indicate diseases that underproduce globulin, such as genetic disorders or leukemia.
To normalize your blood proteins, eat a nutritious, anti-inflammatory diet and avoid diuretic substances like alcohol.
