A/G Ratio Test

The albumin to globulin ratio, often shortened to A/G ratio, compares two major groups of proteins in your blood: albumin and globulins. These proteins serve very different but complementary roles, and the ratio between them helps reveal how well your liver, kidneys, and immune system are functioning.

Albumin is made by the liver and is the most abundant protein in the bloodstream. It helps keep fluid within blood vessels (by maintaining what is called oncotic pressure) and transports substances like hormones, vitamins, and medications. Low albumin levels can result from liver disease, kidney disease, poor nutrition, or inflammation.

Globulins are a group of proteins that include antibodies (immunoglobulins), clotting factors, and proteins that carry iron and lipids. Elevated globulin levels often point to chronic inflammation, autoimmune disease, or certain cancers such as multiple myeloma. Low globulin levels may suggest problems with the immune system or protein loss.

The A/G ratio is calculated by dividing albumin by globulin. In healthy adults, this ratio is usually just above 1. When the ratio drops below normal, it usually means globulin is disproportionately high or albumin is too low. This can happen in conditions like cirrhosis (scarring of the liver), nephrotic syndrome (kidney disease with protein loss), autoimmune diseases, or cancers of antibody-producing cells. A high A/G ratio, which is less common, may indicate immune deficiencies or severe dehydration.

Importantly, an abnormal A/G ratio does not always signal disease. Temporary shifts from dehydration, acute illness, or even lab variability can affect the value. That is why doctors usually interpret the A/G ratio alongside other blood tests, such as total protein, liver function tests, and kidney function markers.

By showing the balance between albumin and globulins, the A/G ratio gives clinicians a simple but powerful lens into multiple organ systems at once: nutrition, liver performance, immune health, and protein metabolism.