A globulin blood test (globulin electrophoresis) measures levels of a group of proteins called globulins. There are four types of globulin proteins: Alpha 1, Alpha 2, beta, and gamma globulin proteins. Globulins make up a little less than half of the proteins in the blood.
These proteins have several functions, including immune defense, transporting substances in the body, and enzyme-related processes. There are two types of globulin test for these proteins: a total protein test or a serum protein electrophoresis test.
This article explains what globulin is tested for and some of the reasons why, such as liver and kidney function assessment. It explains the testing process step by step, and offers insights on what your results may mean.
Globulin Test Purpose
A globulin test is a blood test. It is performed by a healthcare professional who takes a sample of blood from your arm.
If your healthcare provider orders a total protein test, they want to measure the amount of Alpha 1, Alpha 2, and beta globulin proteins in your blood. They will also check albumin levels (a liver protein), as measuring total protein is part of liver function tests, and evaluate the albumin/globulin ratio.
Your healthcare provider may order tests to see how your liver is working if you have symptoms such as:
- Yellow skin (jaundice)
- Nausea
- Vomiting
- Loss of appetite
- Itching
- Constant fatigue
- Swelling or fluid buildup (edema)
Globulin proteins are important to liver and kidney function. A total protein test is a good indication of how the liver is working. Low total protein levels can be a sign of liver disease.
The second type of globulin test is serum protein electrophoresis. This test measures gamma globulin and other trace proteins in the blood. Gamma globulins contain antibodies that help the body attack foreign substances and fight disease.
An increase in gamma globulin proteins can indicate infection, chronic inflammation, and in severe cases, a type of cancer called multiple myeloma.
If your healthcare provider suspects one of these conditions or is specifically concerned about your liver or kidney function, they may order globulin tests.
They will take your medical history, review your list of medications, complete a physical examination, and ask questions about your family health history before ordering a globulin test.
While globulin blood tests can help a healthcare provider to make a diagnosis, they will also use other tests and evaluations to diagnose a specific condition or illness.
Globulin tests can help to diagnose liver disease, kidney disease, malnutrition or malabsorption, immune system disorders, and some forms of cancer.
Risks and Contraindications
Globulin tests require a blood sample. A blood draw (venipuncture) is a routine procedure that can be completed at a healthcare provider's office, clinic, or outpatient lab.
Most people don't experience any problems during or after a blood draw. However, when a vein is punctured it's possible the following can occur:
- Broken blood vessels under the skin (hematoma)
- Dizziness or lightheadedness
- Excessive bleeding
- Infection resulting from skin puncture
While they do not typically occur, these outcomes can be addressed immediately and generally do not have long-term medical consequences.
For healthy people, the overall risk associated with venipuncture is low. The technicians who perform blood draws take steps to lower the risk, such as using single-use needles and appropriate safety precautions.
In most cases, the benefits of the test outweigh the risk associated with having blood taken. However, there are cases, such as a skin infection, where a person should not have a blood draw.
Before the Test
A globulin test may require that you not eat or drink (fast) for several hours or overnight before the blood draw. Your healthcare provider will let you know if you need to fast and for how long. This may mean scheduling the test on a different day than your visit.
It's a good idea to drink extra water the day before your blood draw. When you're properly hydrated, your veins are larger and allow for easier access. Dehydration can make it more difficult for a blood sample to be taken and may increase the risk of complications.
Certain medications can affect the results of the test. Let your healthcare provider know if you take any of the following medications:
- Androgens
- Chlorpromazine
- Corticosteroids
- Dextran
- Growth hormones
- Insulin
- Isoniazid
- Neomycin
- Progesterone and Estrogen (including birth control pills)
- Salicylates
- Steroids
- Sulfonamides
Do not skip or change your medication dose unless your healthcare provider tells you to. If the test will be affected, they may have you take your normal dose at a different time.
Timing
Having blood taken for a globulin test usually only takes a few minutes. However, there are other steps you'll need to complete which can add to the overall time you'll spend on the task.
For example, if you are going to the outpatient lab at a clinic or hospital, you may need to register and provide a copy of the lab order (requisition) from your healthcare provider. The patient registration staff may ask you to confirm the information on file for you, such as your health insurance and emergency contacts, is current.
Your medical records are confidential, and providing this information is a standard part of health information security.
Some healthcare providers can perform blood draws for a globulin test on-site. Others may send you to an external laboratory. The process will be similar, but make sure you have any necessary paperwork with you (or that it's been delivered electronically).
What to Wear
You do not have to remove your clothing or change into a gown to have blood drawn. However, the person taking your blood needs to access the vein in your arm at the crease of your elbow. Wearing layers or a top with sleeves that are easy to push up can be helpful.
Cost and Health Insurance
Having blood drawn for a globulin test is a routine procedure and should not require pre-approval by your insurance. The cost of a specific lab test will vary from one lab and one insurance plan to the next, but most routine blood draws are covered.
Contact your insurance provider before the test to find out how much, if any, out-of-pocket cost there will be.
During the Test
While your healthcare provider will order the test, a healthcare professional called a phlebotomist will take the sample of your blood. Phlebotomists are specially trained and certified to complete blood draws.
Before taking your blood, the technician will ask you to verify your name and date of birth to ensure the vials of blood are appropriately labeled. Your phlebotomist will then:
- Seat you for the blood draw, either in a regular chair or a special chair at the lab
- Look at your veins for the best site, or ask if you have a preference about which arm
- Tie a band around the upper part of your arm to temporarily stop the blood flow
- Wipe the selected site with an antibacterial wipe to sterilize it
- Ask you to squeeze a ball to aid in blood flow, if necessary
- Cover the area with a cotton pad and medical tape when done
Some people experience a slight stinging or pinching sensation as the needle is inserted. The discomfort is typically mild and doesn't last long. If you become dizzy or faint, you will be asked to stay at the lab
for a little while to rest, have a snack, and something to drink.
Let the phlebotomist know if you become dizzy, lightheaded, or feel like you're going to faint during or after having your blood drawn.
After the Test
There is typically no extended recovery period, so you will be able to drive yourself home after the test. It's usually recommended that you refrain from heavy lifting, exercise, or strenuous activity for several hours after the blood draw.
Even if you got dizzy or fainted after the test, healthy people usually recover quickly with rest and fluids. Fainting after having your blood drawn is commonly due to dehydration or low blood sugar (hypoglycemia), especially if you were fasting before the test.
Your healthcare provider may let you know when to expect the results. They will contact you when the test comes back and may ask you to return to the office to go over the results.
Globulin Test Results
Results usually take several days to one week to arrive, depending on the size of the laboratory. Your healthcare provider will receive the results, interpret them, determine what the next steps will be, then relay all of this information to you.
Results from a globulin test come in the form of laboratory values. These numbers indicate whether a person has healthy levels of proteins in their blood.
Globulin Normal Range
Protein globulin levels for adults normally fall between 2.3 and 3.4 grams per deciliter (g/dL). The normal range for total protein is between 6.4 and 8.3 g/dL.
In some cases, these proteins may be elevated. For example, it's normal for these proteins to be higher during pregnancy.
A total protein test also provides the albumin to globulin ratio (A/G ratio). The 1:1 ratio responds to how much of each component there is in the blood (for example, if albumin levels are higher than globulin levels). In general, a value of just above 1 is considered normal.
A low ratio can be a sign of autoimmune disorders, poor kidney function, or liver disease. A high ratio may indicate certain types of cancer or genetic conditions.
Follow-Up
If the results are normal, you won't need any specific follow-up for the test. However, your healthcare provider may want to run other types of tests if you are having symptoms.
If the results are outside the normal range, your healthcare provider may have you do additional blood tests to provide more specific information. Or, you may need imaging tests like an MRI to look for tumors or swollen lymph nodes if cancer is suspected.
A Word From Verywell
A globulin blood test is generally safe for most people, doesn't take a lot of time, and will usually be covered by a health insurance plan. However, you should still understand the procedure and its risks. Talk to your healthcare provider about the results, any additional tests that are needed, and next steps in terms of your treatment options.
Frequently Asked Questions
What is sex hormone binding globulin?
Sex hormone binding globulin (SHBG) is a protein made by your liver that binds the hormones estrogen, dihydrotestosterone, and testosterone. Healthcare providers may order a blood test to check the levels of this protein to diagnose hormone-related disorders such as androgen deficiency or hypogonadism.
What does it mean if your albumin to globulin ratio is high?
If your protein level is high, you may have a gastrointestinal problem, or it may be a sign of cancer, autoimmune disease, or a genetic disorder. But being on bed rest for too long, dehydration, and problems during the blood draw can also cause a high reading. Your healthcare provider will likely order additional tests.
Can exercise lower globulin levels?
Yes. Research shows that aerobic and strength exercises may lower globulin levels in a way that is believed to help with overall health. Exercise also may reduce stress, which has been shown to affect globulin levels in some studies.