The total protein test is a urine or blood test that assesses protein levels in the body. Age, diet, and other factors can affect the results. Atypical levels may be a sign of inflammation, liver disease, or other health conditions.

Doctors may refer to the urine version of this test as “urinary protein” or “protein in the urine” tests. Total protein tests can help diagnose liver and kidney diseases, along with other conditions.

In this article, we discuss the total protein test, how to interpret the results, and what normal or abnormal protein levels might mean.

Share on Pinterest
Sebastian Condrea/Getty Images

Total protein tests measure the total number of proteins present in bodily fluids. Proteins serve as building blocks for many organs, hormones, and enzymes, and so are essential for overall health.

The test examines protein in either urine or the portion of the blood that medical professionals call the “serum.”

Blood test

A serum total protein test measures the amount of albumin and globulin present in the serum portion of the blood. To a lesser extent, it also measures other proteins.

Albumin protein accounts for half of the total protein found in blood plasma. It regulates pressure in the plasma to prevent water from leaking out of blood vessels.

Globulin proteins vary in size, weight, and function. They include alpha, beta, and gamma globulins.

Urine test

Urinary protein testing looks at how much protein there is in a urine sample. The kidneys filter albumin and other proteins from the blood, so urine can contain small amounts of protein.

However, problems with the urinary tract, such as chronic kidney disease, can cause large amounts of protein to leak into the urine. A urine protein test detects if there is too much.

The typical range for protein levels in blood serum is 6–8 grams per deciliter (g/dl). Of this, albumin makes up 3.5 to 5.0 g/dl, and the rest is total globulins. However, it is important to note that these ranges may vary between different laboratories.

Usually, a person’s body eliminates less than 150 milligrams (mg) of total protein and less than 30 mg of albumin through the urine every 24 hours.

High or low serum or urine protein levels do not always signal a chronic medical condition. Factors that can affect a person’s protein levels include:

When a person is pregnant, they may need to have urine tests for signs of proteinuria, which is excess protein in the urine.

Urinary protein that exceeds more than 300 mg of protein per day may indicate preeclampsia, which is a potential complication of pregnancy that causes high blood pressure and other effects.

A doctor may order a serum total protein test during a routine health checkup as part of a comprehensive metabolic panel (CMP).

Doctors may also use a total protein test to help diagnose a variety of diseases that affect protein levels. They may recommend one if a person has:

  • unexpected weight loss
  • loss of appetite
  • fatigue
  • edema, or swelling from excess fluid
  • difficulty urinating
  • nausea or vomiting
  • symptoms of nutritional deficiency

People who have medical conditions that affect their digestive tract, liver, or kidneys may take total protein tests during follow-up visits to monitor their condition.

A doctor will look at the results of the serum total protein test along with other test results to help diagnose medical conditions. They will analyze the results in the context of a person’s overall CMP.

If protein levels are not typical, the doctor may recommend further tests.

What do high protein levels mean?

High serum total protein levels can indicate the following health conditions:

What do low protein levels mean?

Low serum total protein levels may suggest any of the following health conditions:

Albumin to globulin ratio

Alongside the serum total protein level, a laboratory may calculate the albumin to globulin (A/G) ratio in the bloodstream.

A low A/G ratio may be due to an overproduction of globulin, underproduction of albumin, or loss of albumin, which may indicate the following:

  • an autoimmune disease
  • cirrhosis, or scarring of the liver
  • kidney disease
  • multiple myeloma

A high A/G ratio may suggest:

  • an underproduction of antibodies
  • leukemia, or cancer of the bone marrow

A healthcare provider administers a total protein test in a clinic or other healthcare setting. Unless a doctor says otherwise, people do not need to make any special preparations before taking the test.

A serum total protein test involves drawing a sample of blood from a vein located in the arm. A healthcare provider or phlebotomist will tie an elastic band around the upper arm to make the veins easier to find. They will insert the needle into a vein. Blood from the vein will pass through the needle and into a collection tube.

Once the healthcare provider collects enough blood, they will remove the needle and the elastic band from the arm, apply pressure to the injection site, and cover the wound with a dressing if necessary.

A urine total protein test involves collecting a sample of urine and then giving it to a healthcare professional. People collect the sample at home or in a healthcare setting. Some tests involve collecting the urine over a 24-hour period.

Proteins play essential roles in supporting vital bodily functions, such as digestion, blood clotting, and energy production.

A doctor may perform a total protein test during a routine health checkup, or if a person has specific symptoms, to measure the amount of protein present in the blood or urine.

A total protein test can detect typical or atypical protein levels, which can help diagnose medical conditions, such as kidney and liver diseases.