Serum or Plasma Substance Concentration of Neopterin

Why Is This Test Done?

Your doctor may order this test to evaluate immune system activity, check for infections (such as tuberculosis or viral infections), or monitor conditions like autoimmune diseases, cancer, or organ transplant rejection. Neopterin levels can also be useful in diagnosing or managing certain neurological or inflammatory disorders.

What Does a High or Low Level Mean?

Elevated neopterin levels often indicate an active immune response, infection, or inflammation. Lower-than-normal levels may suggest suppressed immune activity, though this is less common and depends on clinical context. Your doctor will interpret results in relation to your symptoms and medical history.

How Is This Test Performed?

A blood sample is drawn from a vein in your arm. The sample is then processed to separate serum or plasma, where neopterin is measured using a specialized immunoassay technique. No special preparation is needed, but fasting may be recommended depending on your doctor’s instructions.

What Are Common Causes of Abnormal Results?

High neopterin levels can result from infections (bacterial, viral, or fungal), autoimmune diseases (like lupus or rheumatoid arthritis), certain cancers, or organ transplant rejection. Chronic stress or exposure to toxins may also contribute. Low levels are less frequently associated with specific conditions but could indicate immune suppression in rare cases.