2025 CPT code 86331
Effective Date: N/A Pathology and Laboratory Procedures > Immunology Procedures Feed
Immunodiffusion; gel diffusion, qualitative (Ouchterlony), each antigen or antibody
Modifiers may be applicable. Refer to current CPT guidelines for appropriate modifier usage.
Medical necessity should be established by documenting the patient's signs, symptoms, or clinical condition that warrants the immunodiffusion test. The documentation should link the test results to the patient's diagnosis and treatment plan.
The lab analyst performs the technical aspects of the test, interprets the results, and may contribute to the diagnostic process.
In simple words: This test checks your sample (like blood, urine, or spinal fluid) for specific substances that can trigger an immune response or for proteins that fight off infections.A small amount of your sample and a matching substance are placed in separate little wells on a special plate. These substances then spread out on the plate, and if they react, they form a visible line. This helps figure out if you have certain infections or immune system issues.
The lab analyst performs qualitative immunodiffusion, by Ouchterlony method, to evaluate a patient’s sample for specific types of antigens (foreign substances that cause an immune response), or for certain proteins, called immunoglobulins (also called antibodies), that activate as part of the immune response to neutralize specific invaders such as bacteria or viruses. The lab analyst performs the technical steps to test the patient’s sample (typically serum, urine, or cerebrospinal fluid) for antibodies or antigens, using Ouchterlony, or double, immunodiffusion. The test may include pipetting the sample into a well in an agarose plate and pipetting a complementary antibody or antigen into another well. The antibodies and antigens spread out (diffuse) into the gel and form white lines of precipitated antibody antigen complexes where they meet. The analyst then interprets the results.This code is reported once for each antigen or antibody.
Example 1: A patient with suspected aspergillosis (a fungal infection) undergoes immunodiffusion testing to identify specific antibodies or antigens related to the fungus., A patient with recurring infections undergoes immunodiffusion testing to evaluate their immune response and identify potential deficiencies in specific antibodies., Immunodiffusion is used to detect the presence of specific antigens in a patient's cerebrospinal fluid to aid in the diagnosis of meningitis.
Documentation should include the reason for the test, the type of specimen collected, the specific antigen or antibody tested for, and the interpretation of the results.
- Specialties:Immunology, Pathology, Infectious Disease
- Place of Service:Independent Laboratory, Hospital Inpatient, Hospital Outpatient