CPT® Code 86331

The CPT® Code 86331 refers to a specific immunodiffusion test known as gel diffusion, which is performed qualitatively to detect the presence of antibodies or antigens in a patient's serum. This test is particularly relevant in the context of hypersensitivity pneumonitis, a condition that arises from an immune response to inhaled organic antigens. The procedure involves measuring precipitation antibodies that are associated with this condition. The test is conducted using a method called the Ouchterlony technique, which allows for the qualitative assessment of these antibodies. In the context of hypersensitivity pneumonitis, the test includes various antigens such as Aspergillus fumigatus, Aureobasidium pullulans, and others, which are known to trigger immune responses in susceptible individuals. The presence of precipitation antibodies is typically indicative of active cases of hypersensitivity pneumonitis; however, it is important to note that these antibodies may also be found in asymptomatic individuals. Therefore, while a positive result can support a diagnosis in conjunction with a patient's clinical history and symptoms, a negative result does not definitively exclude the diagnosis of hypersensitivity pneumonitis. The blood sample required for this test is obtained through a venipuncture, which is a separately reportable procedure. The serum collected is then subjected to qualitative immunodiffusion to identify the presence of the relevant antibodies.