Granulocyte Lymphocyte Ratio (GLR) from Whole Blood

The GLR test measures the balance between granulocytes and lymphocytes, two major types of white blood cells found in a sample of your blood.

The GLR compares the number of granulocytes to lymphocytes. Granulocytes are part of your body’s first line of defense against bacteria and infections, while lymphocytes help fight viruses and support long-term immunity. This ratio can shift depending on your health status, immune response, or underlying conditions.

Your healthcare provider may order this test if you have signs of infection, inflammation, or an immune system condition, or as part of a routine workup to help evaluate your overall health.

Your doctor may order a GLR test to assess immune function, evaluate infections (like bacterial vs. viral), check for conditions like chronic inflammation, or monitor treatment responses in certain diseases (e.g., cancer, autoimmune disorders). It’s sometimes used alongside other blood tests to get a clearer picture of your immune system.

This test is performed with a simple blood draw. A healthcare professional will clean your skin, insert a small needle into a vein, usually in your arm, and collect a small blood sample into a tube.

A small blood sample is drawn from a vein, typically in your arm. The sample is analyzed in a lab to count and compare the types of white blood cells. No special preparation is needed, but fasting may be advised depending on your doctor’s instructions.

Common uses of the GLR test include helping to detect infections, monitoring inflammatory conditions, evaluating immune system function, and supporting the diagnosis and follow-up of certain blood disorders.

Common reasons for testing include diagnosing or monitoring infections (e.g., pneumonia, urinary tract infections), evaluating immune deficiencies, assessing response to chemotherapy or other treatments, or investigating unexplained fevers or fatigue.