Allergy-Based Diagnostic Tests

Allergy-Based Diagnostic Tests 

biological reactions used in the diagnostics of a number of diseases—mainly infectious—based on increased sensitivity of the organism caused by an allergen (in the case of infectious diseases, by the pathogen or its toxin). Upon administration of the appropriate allergen, the organism responds with a local or general reaction, on the basis of which it is possible to decide whether a particular disease is present. The diagnostic value of such tests is derived from their specificity, sensitivity, and safety for the human or animal patient being studied. To this group of tests belong the Pirquet and Man-toux reactions for tuberculosis, the Burnet reaction for brucellosis, and the Schick reaction for diphtheria. Allergy-based diagnostic tests can also reveal increased sensitivity of the organism to a substance which produces bronchial asthmatic seizures or other allergic illnesses.

Allergy-based diagnostic tests are used in veterinary medicine in the diagnosis of glanders, tuberculosis, brucellosis, paratuberculous enteritis, tularemia, toxoplasmosis, and certain other infectious and infestive diseases. The principal merit of these tests in veterinary practice is their simplicity, both in individual and mass study; they indicate that an animal is infected even in the absence of any clear clinical signs of disease. In the diagnosis of glanders in solid-hoofed animals, mallein allergen is used; for tuberculosis in animals, tuberculin; and for brucellosis, abortin, brucellisate, and brucellohydrolysate. In veterinary practice, the preparations are applied to the conjunctiva (mallein and tuberculin) or administered intracutaneously.