Immunoglobulin G (IgG) Subclass 1 and 2 Quantification in Serum

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like frequent infections, unexplained fatigue, or if you’re being evaluated for conditions like immunodeficiency, autoimmune diseases, or after receiving certain treatments that affect the immune system. It may also be used to monitor immune response to vaccines or treatments like chemotherapy.

What to Expect Before the Test

No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before the draw if your lab requires it, but this is not always the case. Bring any medications or supplements you’re taking to your appointment.

What Happens During the Test

A healthcare professional will insert a small needle into a vein in your arm to collect a blood sample. The process usually takes a few minutes. You may feel a brief pinch, but most people tolerate it well. The blood sample is then sent to a lab for analysis using an immunoassay method.

What the Results Mean

Results show the concentration of IgG subclasses 1 and 2 in your serum. Abnormal levels may suggest immune system issues, such as low production of these proteins or overactivity in certain immune pathways. Your provider will interpret the results in the context of your overall health and symptoms.