Plasma protein tests are blood tests that detect the amount of proteins in the blood. This lab work is usually ordered as part of a comprehensive metabolic panel (CMP) during a physical exam. The tests can help your doctor determine your overall health. Plasma protein tests are also known as a total protein test.
Your doctor may also order plasma protein tests if they believe that you have certain underlying health conditions, such as inflammation or certain autoimmune conditions like rheumatoid arthritis and celiac disease. Depending on your condition, your doctor may order follow-up blood work as part of your treatment plan.
You have two main types of plasma proteins in your blood:
- albumin, which has many important roles, such as providing amino acids for your body tissues and stopping fluid leaks
- globulin, which helps support your immune system, blood clotting, and other vital functions
The levels of albumin and globulin in your blood may rise or fall if you have certain conditions. A plasma protein test can detect an underlying condition by measuring these protein levels.
Certain symptoms may indicate whether you have high or low protein levels in your blood.
Symptoms of low protein levels can include:
- bruising easily
- slow clotting of blood after an injury
- brittle or ridged nails
- hair loss
Symptoms of high protein levels can include:
- pain in your bones
- numbness or tingling in your hands, feet, or legs
- loss of appetite
- weight loss
- excessive thirst
- frequent infections
Symptoms may vary depending on the condition causing your abnormal plasma protein levels.
Doctors order plasma protein tests to measure the amounts of specific proteins in the blood. Total protein levels may be higher or lower than average in the case of certain disorders, including:
Abnormal protein counts can indicate potential health problems. Higher-than-normal protein levels are associated with:
- bone marrow disorders
Lower-than-normal plasma protein levels may indicate:
- severe malabsorption of nutrients and malnutrition
- kidney or liver disease
- bowel problems
In addition to albumin levels, your protein test may also detect blood levels of globulin. This is called an A/G ratio. A normal A/G ratio is just above 1, with albumin being higher than globulin.
If this ratio is off, it can affect your total protein count. Low A/G ratios are associated with too much globulin, which can be caused by autoimmune diseases. High A/G ratios can be a sign of leukemia or bowel disorders.
Once your doctor gives you an order for a total protein test, you should have it done immediately. Some doctor’s offices provide in-house blood work, so you may be able to have your blood drawn during your appointment. In many cases, you’ll have to visit a lab to get your blood drawn. Make sure that the lab you go to is covered by your insurance.
There is no special preparation for this blood test.
Tell your doctor about any medicines you’re taking, as they may interfere with the results. Birth control pills and estrogen medicines may decrease blood protein levels.
Like other blood work, plasma protein tests carry few risks. If you are sensitive to needles, you may feel slight pain or discomfort. The process normally takes a few minutes, but it might take longer if you have smaller veins. You may experience bruising at the puncture site or temporary dizziness. Call your doctor if you have signs of infection, such as redness, inflammation, and discharge, after your blood is taken.
Be mindful of your lab technician’s use of tourniquets during the blood drawing process. These arm-compressing devices can produce false results if they’re kept on for longer than a few minutes. With a tourniquet, your total protein levels may be measured as higher than they really are. Once blood has been collected, the technician should release the tourniquet before withdrawing the needle.
It’s important to have normal levels of plasma proteins during your pregnancy. Studies suggest that low levels of pregnancy-associated plasma protein A (PAPP-A) in early pregnancy are related to certain complications. These complications can include:
- intrauterine growth restriction (IUGR)
- premature birth
- low birth weight
- hypoxia, or a lack of oxygen for the baby at birth
- Down syndrome
- gestational diabetic mellitus
Normal results do not require any follow-up tests, unless your doctor has other concerns about your CMP. If your total protein test results are abnormal, your doctor will likely order a series of follow-up tests, such as:
- C-reactive protein tests to evaluate for inflammation
- immunoglobulin A (IgA) tests to measure antibodies and help diagnose autoimmune diseases
- liver enzyme tests to detect related diseases and inflammation
- protein electrophoresis to look for underlying bone marrow disorders
If your tests indicate that your abnormal protein levels are caused by any of the following serious conditions, your doctor will recommend treatments to address them:
- heart disease
- liver disease
- kidney disease
- cancer, such as multiple myeloma
Following up with your doctor after receiving abnormal test results is essential to maintaining your health and quality of life. There are many treatment options for the causes of abnormal plasma protein levels. Early detection is key to resolving the medical issues causing high or low levels of plasma proteins.