method of Ouchterlony, are often used to detect high levels of specific IgG, as can occur in patients with hypersensitivity pneumonitis. Specific cell-mediated immunity can be assessed by several methods, including the lymphocyte transformation assay and assays involving the production of mediators or cytokines. These tests are generally regarded strictly as research assays, however, and are not usually used to evaluate patients or populations.
As with skin tests, the accuracy of any immunodiagnostic test depends on the characteristics of the test reagents, and in particular on the allergen reagent. Standardization and characterization of allergen reagents used for immunodiagnostic tests are imperative. Similarly, the existence and characterization of control antibody, whether polyclonal or monoclonal, would be valuable for standardization and quality control of immunodiagnostic tests. Ideally, minimal standards for quality control should be devised for labs reporting results of tests to detect specific immunologic responses to indoor allergens.
Diseases such as asthma and hypersensitivity pneumonitis are characterized by decrements in lung function that vary over time. Pulmonary function tests, which measure these decrements and any improvements that may occur, have many applications in clinical medicine and research related to indoor allergens. These tests include spirometry (the most reliable pulmonary function test), peak-flow measurement, lung-volume measurement using gas dilution or body plethysmography, diffusing-capacity testing, exercise studies, and rhinomanometry. The choice of the appropriate pulmonary function test depends on the requirements of the specific application.
One drawback of many pulmonary function tests is that they must be administered by medical personnel or trained technicians. Peak-flow measuring devices are the exception. These devices are less reliable than some other technologies, but they are easily portable and can be self-administered—making them useful in the diagnosis and management of asthma.
The process of assessing exposure to indoor allergens is complex. The relevant contaminants, contaminant sources, and environmental exposure media must be identified. The manner in which allergens are transported through each medium and how the contaminants are chemically and physically transformed must be determined. In addition, the allergen's routes of entry into the body, the intensity and frequency of contact between the