Pirquet Reaction

(also called Pirquet test), a cutaneous, allergic diagnostic test to discover increased sensitivity in humans to the causative agent of tuberculosis. The Pirquet reaction was proposed by the Austrian pathologist and pediatrician C. Pirquet in 1907. A drop of tuberculin, which is prepared from killed tuberculosis mycobacteria, is applied to the skin of the forearm after a small incision is made. The degree of swelling at the incision site is observed in two to three days. A positive Pirquet reaction can result from the body’s previous contact either with the causative agent of tuberculosis or with antituberculosis inoculations. The test is used in schools to detect the presence of tuberculosis mycobacteria in children. Those children who have a positive Pirquet reaction when the test is first administered are examined by a phthisiologist. The test loses its diagnostic value in cases where extensive intracutaneous inoculation against tuberculosis has taken place. However, modified versions of the test are used in phthisiatry to monitor the development of the disease. The Mantoux test, a more sensitive, intradermal tuberculin test, is used to select uninfected persons for intradermal immunization.