Medically Reviewed By William C. Lloyd III, MD, FACS
— Written By Kristi Van Winkle, RN
Updated on November 15, 2022
Read on to learn more about the A/G ratio and what conditions could cause it to be higher or lower than normal.
What is an A/G ratio?
Your A/G ratio is the amount of albumin compared to the amount of globulin in your blood. Albumin and globulins are the two main types of proteins in your blood.
- Albumin helps transport substances through your body, such as vitamins, hormones, and medication. It also prevents blood from seeping out of your blood vessels and binds fatty acids, keeping them in a soluble form while in the blood. The liver produces albumin.
- Globulins are a group of different types of proteins that help move nutrients through your body and help you fight infections. The liver produces some globulins, and your immune system makes others.
A total protein test and an A/G ratio test measure your blood’s total amount of protein and the amount of albumin you have compared with globulin.
Some diseases lower the albumin level while raising one or more types of globulins. The movements and fluctuations of proteins, fluids, and other substances in your blood can paint a picture of what is happening in your body.
What is the normal range for the A/G ratio?
The albumin/globulin ratio is the albumin in your blood divided by the amount of globulins. The standard A/G ratio range is
Although the “within normal limits” values for protein levels and other levels vary from laboratory to laboratory, the usual total serum protein level is about 6 to 8 grams per deciliter (g/dL).
Albumin makes up about
What causes a high A/G ratio?
If your A/G ratio is high, it could indicate an underlying genetic disorder or leukemia. Leukemia is a cancer that affects the production and function of blood cells.
A high A/G ratio can be caused by either elevated albumin levels or low globulin levels. This could indicate a few other conditions as well:
- dehydration
- pregnancy
- albuminuria, or high albumin levels in urine caused by kidney disease
- malnutrition
What causes a low A/G ratio?
If your A/G ratio is low, it could indicate:
- certain autoimmune diseases, such as lupus
- liver disease, such as cirrhosis
- kidney disease
Low albumin levels or high globulin levels can cause a low A/G ratio. Other conditions that may cause such fluctuations include:
- chronic infections like tuberculosis or hepatitis
- pancreatitis
- type 2 diabetes
- certain cancers, like multiple myeloma or lung cancer
How do doctors test the A/G ratio?
Your doctor may order an A/G ratio test by itself or as part of a comprehensive metabolic panel (CMP). Because it measures proteins and other substances in your bloodstream, your doctor may order a CMP as part of regular blood work. A CMP can help diagnose kidney, liver, or nutritional problems.
A phlebotomist will draw blood from a blood vein in your hand or arm with a small needle. You may feel a pinching sensation when the phlebotomist inserts the needle, but once the draw is complete, you should not feel any more pain at the site. You may have some bruising in the area after the draw, but a blood draw usually has no other side effects.
This blood will be sent to the lab and analyzed. Your doctor will use these numbers and other factors to determine your diagnosis.
Generally, you do not need to do anything special to prepare for this test. Still, a fasting blood sample is sometimes preferred, so you may be asked not to eat for several hours before the blood draw.
Drink plenty of water before the test for a more accurate test result. Dehydration can cause your protein levels to appear higher than they are.
Before the test, make sure your doctor knows what medicines, vitamins, supplements, and any illegal drugs you take.
If your levels come back abnormal, your doctor may want a repeat A/G ratio test or CMP, or they may order other blood or urine tests for confirmation. Your doctor may also want to run some scans, such as a CT or MRI, to check your liver or kidneys to see whether your A/G ratio is abnormal.
Who might need to get their A/G ratio tested?
Your doctor may order an A/G ratio test or a CMP if they are concerned you may have certain conditions, such as:
- protein loss from your digestive tract
- leukemia, or other blood diseases
- high infection risk
- kidney disease
- liver disease
- malnutrition
- diabetes
- lupus
Talk with your doctor if you have any symptoms that indicate abnormal protein levels in your blood, which could mean liver or kidney problems. These symptoms may include:
- jaundice, or yellowing of your eyes or skin
- swelling in your feet, legs, or abdomen
- unexplained weight loss
- poor appetite
- nausea and vomiting
- unexplained fatigue
- unexplained itching
- blood in your urine
- abdominal pain
Summary
The A/G ratio is a blood test that measures protein levels. Your doctor may order an A/G ratio as part of a complete metabolic profile or as a stand-alone blood test.
An abnormal A/G ratio can alert your doctor to the possibility of specific health concerns, such as liver disease, kidney disease, or leukemia.
But you could also have an abnormal value for other reasons, such as faulty lab techniques, equipment, or other medical conditions. In addition, many things can affect blood test results. Talk with your doctor about liver, kidney, or blood disease symptoms.
Your doctor will discuss your lab results with you and their concerns and possible treatment plans. Talk with your doctor if you have any questions about your lab results or symptoms.
