Neutrophil-to-lymphocyte ratio (NLR) in serum/plasma

What Is Neutrophil-to-Lymphocyte Ratio (NLR)?

Neutrophils and lymphocytes are both part of your immune system. Neutrophils are the first responders to infections, while lymphocytes help fight long-term infections and regulate immune responses. The NLR compares these two cell types to gauge overall immune activity. This ratio can be useful in monitoring conditions like infections, chronic inflammation, or certain cancers.

When Might You Need This Test?

Your doctor may order an NLR test if you have symptoms like fever, fatigue, or signs of infection. It’s also sometimes used in cancer care to track immune responses or after surgeries to check for inflammation. Some specialists use it to guide treatment decisions for conditions like heart disease or autoimmune disorders.

How Is the Test Done?

A small blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab where it’s analyzed to count neutrophils and lymphocytes. The results are expressed as a ratio (e.g., 1.5:1). No special preparation is needed, but fasting may not be required unless your doctor specifies otherwise.

What Do the Results Mean?

Results can vary depending on your health status. A higher NLR may suggest more neutrophils relative to lymphocytes, which could indicate infection, stress, or inflammation. A lower NLR might suggest a stronger immune response or less inflammation. Your doctor will interpret the results in the context of your overall health and symptoms.