CPT® Code 82787

The CPT® Code 82787 refers to the testing of immunoglobulin subclasses, specifically IgG1, IgG2, IgG3, or IgG4. This procedure involves measuring the levels of these specific immunoglobulin subclasses in blood or other body fluids, such as saliva or cerebrospinal fluid (CSF). Immunoglobulins, commonly known as antibodies, play a crucial role in the immune system by identifying and neutralizing pathogens like bacteria and viruses. The evaluation of immunoglobulin levels is essential for diagnosing various medical conditions, including autoimmune diseases, allergies, and certain types of cancers, such as multiple myeloma or macroglobulinemia. The presence and levels of immunoglobulins can provide valuable insights into a patient's immune function. For instance, individuals with frequent infections may undergo this test to assess whether they have low levels of immunoglobulin IgG, which is vital for combating infections. Additionally, monitoring immunoglobulin levels can help evaluate the effectiveness of treatments in patients with conditions like cancer or infections caused by Helicobacter pylori. There are five major types of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, each serving distinct functions in the immune response. IgA is primarily found in mucosal areas, providing a first line of defense against pathogens. IgD is present in tissues lining body cavities, while IgE is associated with allergic reactions. IgG, the most abundant antibody in circulation, is critical for fighting infections and has four subclasses—IgG1, IgG2, IgG3, and IgG4—each tailored to respond to different types of pathogens. For example, IgG1 is particularly effective against viral infections, while IgG2 targets certain bacterial infections. In cases where individuals exhibit selective deficiencies in one or more IgG subclasses, this test can help identify the specific subclass that is lacking, despite normal total IgG levels. The collection of specimens for this test can be performed through venipuncture for blood samples, spinal puncture for CSF samples, or saliva collection. The methodology for testing varies based on the specimen type and the specific immunoglobulin being analyzed. It is important to use the appropriate CPT codes for reporting these tests, with 82784 designated for individual immunoglobulin determinations (IgA, IgD, IgG, or IgM), 82785 for IgE determination, and 82787 for the assessment of IgG subclasses.