What Is a Total Serum Protein Test?

Medically Reviewed by Sabrina Felson, MD on May 28, 2023
3 min read

As part of a regular health checkup, your doctor may order blood work. This often includes a total serum protein test. It measures the amount of protein in your blood. This can give you insight into your general health. It can also be used to look for some serious health problems.

Your liver’s in charge of making most of the proteins that are in your blood. They are important for good health.

Two of the key ones are:

Albumin. This carries medicines and hormones throughout your body. It also helps with tissue growth and healing.

Globulin. This is a group of proteins. Some of them are made by your liver. Others are made by your immune system. They help fight infection and transport nutrients.

The total serum protein test measures all the proteins in your blood. It can also check the amount of albumin you have compared to globulin, or what’s called your “A/G ratio.”

Healthy people have a little more albumin than globulin, but if you’re sick, this won’t be the case.

Your doctor could order this test as part of a routine checkup. But they may also want to:

  • Make sure you’re getting enough nutrition
  • Screen for liver, kidney, or blood disease
  • See if you’re at risk for an infection
  • Find the cause for symptoms you’re having

A technician will take a sample of your blood. Sometimes this is taken from a vein in your arm. It can also be done with a finger prick. For newborns, it’s done with a “heel stick” -- the blood is drawn through a small puncture of the heel.

Some drugs, like birth control pills, reduce the amount of protein in your blood. This can skew your test results. Make sure your doctor knows all the medicines you’re taking, as well as any herbs, vitamins, or illegal drugs.

Make sure to drink plenty water before taking this test. Being dehydrated can change the results.

The lab results should be back in about 12 hours.

Every lab has a slightly different range of what’s considered normal. Because of that, your doctor will take your health and past lab work into account when they look at your results. Numbers and levels that seem “off” could be normal for you.

Low total protein: You could have a liver or kidney disorder, or a digestive disorder like celiac disease (your body can’t absorb protein the way it should).

High total protein: Too much protein in your blood can be a sign of chronic infection or inflammation (like HIV/AIDS or viral hepatitis). It can also be an early sign of a bone marrow disorder.

Low A/G ratio: This might be the sign an autoimmune disorder, where your body’s immune system attacks healthy cells. It can also point to kidney disease or cirrhosis, which is inflammation and scarring of the liver. In some cases, a low A/G ratio can be a sign of a tumor in your bone marrow.

High A/G ratio: This can be a sign of disease in your liver, kidney, or intestines. It’s also linked to low thyroid activity and leukemia.

If your doctor feels any of your levels are too high or low, you may need to have more precise blood or urine tests. For instance, your doctor may give you a serum protein electrophoresis (SPEP) if your total serum protein is high or if you have otherwise unexplained signs and symptoms that might suggest you could have a plasma cell disorder, like multiple myeloma. Your doctor will give you more details about your results and let you know what, if any, other tests you need.