You opened your blood test results and found a flag next to "globulin" or "A/G ratio," two lines you may never have noticed before. They are part of a standard comprehensive metabolic panel, the same panel that checks your liver and kidneys. This guide explains what globulin is, what the A/G ratio blood test measures, the normal range, what high or low results can mean, which follow-up tests doctors use, and why a small number of people end up being watched for a condition called MGUS.
Told you have MGUS, smoldering myeloma, or multiple myeloma?
Studies are looking at new ways to watch, treat, and prevent progression. See which ones are recruiting near you.
What globulin is
Globulins are a group of proteins in your blood. Some are made by the liver and help carry nutrients and form blood clots. Others, called gamma globulins or immunoglobulins, are antibodies made by your immune system to fight infections.
Your other main blood protein is albumin, the most abundant one. Albumin is made by the liver, keeps fluid inside your blood vessels, and carries hormones, medicines, and vitamins. Most labs do not measure globulin directly: they measure total protein and albumin, and globulin is what is left.
What the A/G ratio blood test measures
The albumin/globulin ratio, or A/G ratio, is your albumin divided by your globulin. Because the body normally has a bit more albumin than globulin, a typical ratio is slightly more than 1. The ratio is useful because it can shift even when total protein looks normal, for example when albumin goes down and globulin goes up at the same time.
Globulin normal range and A/G ratio normal range
Ranges differ slightly between labs, so always compare your result with the range printed on your own report. One commonly used set of adult ranges is:
- Total protein: 6.3 to 8.0 g/dL
- Albumin: 3.9 to 4.9 g/dL
- Globulin: 2.0 to 3.5 g/dL
- A/G ratio: slightly more than 1
A result just outside the range on a single test is common. Doctors look at the pattern: whether albumin, globulin, or both changed, whether other results such as liver enzymes or kidney tests are also off, and whether you have symptoms.
Things that can shift your result for a short time
Several everyday factors can move these numbers without meaning there is a disease:
- Dehydration, including after diarrhea, which concentrates the blood and can raise both albumin and globulin.
- Pregnancy. Low albumin is normal in pregnancy, and globulin tends to rise and then return to normal after birth.
- A recent infection or inflammation, which raises some globulins for a while.
- Some medicines, including corticosteroids, birth control pills, and insulin.
Tell your doctor about every medicine you take, but do not stop any of them before the test unless you are told to.
What high globulin can mean
A high globulin level means the blood is carrying more of these proteins than usual. Most often this reflects the immune system at work. Possible causes include:
- Infections, including long-lasting ones such as HIV, viral hepatitis, and tuberculosis.
- Autoimmune and inflammatory diseases, such as lupus and rheumatoid arthritis.
- Chronic liver disease, where albumin often falls while globulin rises.
- Dehydration.
- Less often, blood cancers such as multiple myeloma, Waldenström macroglobulinemia, or lymphoma.
What a low A/G ratio means
A low A/G ratio means there is relatively less albumin, more globulin, or both. It is linked with autoimmune disease such as lupus, liver disease including cirrhosis, and kidney disease, in which albumin can leak into the urine. It can also be seen when a single type of antibody is being overproduced, which is why doctors sometimes order a follow-up test, described below.
What low globulin can mean
Low globulin is less common. It can be a sign of liver disease, kidney disease, or malnutrition. It can also mean the body is making too few antibodies, a condition called hypogammaglobulinemia.
Most people with low antibody levels have an acquired form, caused by medicines such as corticosteroids, immunosuppressants, some anti-seizure drugs, and chemotherapy, or by conditions such as nephrotic syndrome, HIV, chronic lymphocytic leukemia, lymphoma, or multiple myeloma. A smaller group has an inherited immune disorder; in adults the most common is common variable immunodeficiency (CVID). The typical sign is infections that keep coming back or last a long time, such as sinus infections, bronchitis, or pneumonia.
What a high A/G ratio means
A high A/G ratio usually reflects low globulin. It can be linked with some genetic disorders and with certain leukemias, and your doctor may check immunoglobulin levels if it stays high.
Follow-up tests your doctor may order
If your globulin or A/G ratio stays outside the range, the next step is usually serum protein electrophoresis (SPEP). This test splits your blood proteins into groups and shows which type of globulin is high or low. A broad rise across many antibodies usually points to infection or inflammation. A single narrow spike, called an M protein or monoclonal protein, means one group of plasma cells is making large amounts of the same antibody.
Doctors may also order immunoglobulin levels (IgG, IgA, IgM), immunofixation to identify the type of M protein, and a serum free light chain test. Liver and kidney tests help sort out the other causes; if your liver enzymes or alkaline phosphatase were also flagged, see what high ALT means and our guide to alkaline phosphatase.
When an M protein is found: MGUS and smoldering myeloma
Most people with an M protein have monoclonal gammopathy of undetermined significance, or MGUS. It causes no symptoms and does not need treatment. Mayo Clinic researchers report that MGUS is present in more than 3% of people age 50 and older, and that it progresses to multiple myeloma or a related disorder at about 1% per year. That risk does not disappear with time, so people with MGUS have regular blood tests to watch the M protein.
Smoldering multiple myeloma is a step between MGUS and active myeloma: there are more abnormal plasma cells, but no organ damage yet. Until recently the standard was to watch and wait. In November 2025 the FDA approved Darzalex Faspro (daratumumab and hyaluronidase) for adults with high-risk smoldering myeloma, based on the AQUILA trial of 390 people, in which treatment cut the risk of progressing to active myeloma by about half compared with monitoring.
Our guide to new treatments for multiple myeloma covers what is available once myeloma becomes active.
Where research stands
Researchers are studying who with MGUS or smoldering myeloma is most likely to progress, and whether early treatment can prevent active myeloma. Studies are recruiting across the US for MGUS and smoldering myeloma, and many more for active multiple myeloma.
Some of these studies compare a new approach with standard care or with a placebo. Nothing is decided until you have gone through informed consent, and participation is voluntary at every step. You can browse multiple myeloma clinical trials on AllClinicalTrials.com.
Common questions
Is a slightly high globulin level something to worry about? Usually not on its own. A small rise is often linked to a recent infection, inflammation, or dehydration. Your doctor may simply repeat the test, or order protein electrophoresis if it stays high.
What is a normal A/G ratio? Slightly more than 1, because the body normally has a bit more albumin than globulin. Check the range printed on your lab report, since it differs between labs.
Does high globulin mean cancer? Most high globulin results are caused by infection, inflammation, autoimmune disease, or liver disease. Blood cancers such as multiple myeloma are a less common cause, and a protein electrophoresis test helps tell them apart.
Can drinking more water change my globulin result? If you were dehydrated when the blood was taken, your albumin and globulin may read high, and they can come down once you are well hydrated. Water will not change a result caused by a medical condition.
Do I need to fast for an A/G ratio test? The test is usually part of a metabolic panel, which may require fasting for several hours. Your provider will tell you what to do.
Do myeloma study participants get paid? Some studies offer compensation for time and travel, and study related care is typically provided at no cost to participants. Compensation varies by trial and is always described during the informed consent process before you agree to anything.