Serum or plasma mass concentration of immunoglobulin G (IgG) fragments or related peptides (e.g., F(ab')₂ fragments)

What This Test Measures

IgG is the most abundant antibody in your blood, helping fight infections and diseases. When IgG breaks down, it can form smaller fragments like F(ab')₂. This test detects these fragments in your serum or plasma. These fragments may appear if your immune system is overactive, if antibodies are being broken down, or in certain immune-related disorders.

Why It Might Be Ordered

Your healthcare provider may order this test if you have symptoms or conditions linked to abnormal antibody activity, such as immune system disorders, chronic inflammation, or certain autoimmune diseases. It could also be part of a broader evaluation for conditions affecting protein structure or immune response.

Common Conditions Monitored

While less common than standard IgG tests, fragments of IgG may be studied in cases of immune dysregulation, severe infections, or rare genetic disorders affecting antibody function. This test helps track how these fragments behave in your bloodstream.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, typically drawn from your arm. If you’re on blood thinners, let your provider know before the test.