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Hypersensitivity Pneumonitis Profile

Test ID:

705100

CPT code:

86331, 86602 (x3), 86606, 86671

Synonyms:

Extrinsic Allergic Alveolitis Profile

Clinical Use:

Confirm the presence of precipitating antibodies associated with hypersensitivity pneumonitis

Test Information:

Hypersensitivity pneumonitis (HP), also referred to as extrinsic allergic alveolitis (EAA), is an inflammatory lung disease resulting from the inhalation and subsequent sensitization to a wide variety of inhaled organic dusts.1-5 HP is not mediated by IgE. It is associated with progressive pulmonary disability, irreversible lung damage, and mortality in some occupational settings.1-5 Patients often present with intermittent chills, fever, cough, and shortness of breath that begin four to eight hours after exposure to the offending dust.

No single laboratory test is diagnostic for hypersensitivity pneumonitis. Diagnosis is based on a complete environmental history supported by result of chest x-ray, spirometry, and in vitro immunologic tests. Identification of the causative agent is important to allow avoidance of exposure. Double diffusion (Ouchterlony) assays are typically used to determine antigen-specific IgG antibodies. The appearance of precipitin arcs confirms the presence of precipitating antibodies to specific antigens. These antibodies may also be present in individuals not afflicted with HP. The presence of antibodies to the offending dust or antigen confirms exposure but is not diagnostic of HP; however, upon repeated or prolonged exposures, high levels of precipitating IgG antibodies are typically observed.