Immunoassay for Immunoglobulin G (IgG) Subclass 1 (IgG1) in Serum or Plasma

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of immune system issues, such as frequent infections, autoimmune diseases, or if you’re being evaluated for conditions like hypogammaglobulinemia (low antibody levels) or certain immune deficiencies. It may also be used to monitor treatment responses in conditions affecting antibody production.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, which usually takes a few minutes. If you’re taking blood from a vein in your arm, you might feel a slight pinch or discomfort, but it’s typically over quickly.

What the Test Results Mean

Results are compared to a general reference range for IgG1 levels in healthy individuals. While specific reference ranges can vary slightly by lab, lower than expected levels may suggest immune system challenges, while higher levels might indicate overactive immune responses or certain medical conditions. Your healthcare provider will interpret the results in the context of your overall health and symptoms.

Common Conditions Monitored or Diagnosed With This Test

This test can help diagnose or monitor conditions such as primary immunodeficiency diseases, autoimmune disorders (like rheumatoid arthritis or lupus), chronic infections, or after treatments that may affect antibody production (e.g., chemotherapy or certain medications). It may also be used in research or specialized clinical settings to study immune function.