Pirquet

Pirquet is a surname. The best known bearer is Clemens von Pirquet (1874–1929), an Austrian physician and pediatrician who helped lay the foundations of modern allergy and immunology. He is associated with the development of the Pirquet test, a cutaneous tuberculin skin test used in the early 20th century to detect tuberculin sensitivity.

The Pirquet test involved applying a small amount of purified tuberculin to the skin, typically on the forearm, and creating a shallow scarification or scratch to introduce the antigen. The site was observed after about 24 to 72 hours for signs of a hypersensitivity reaction, such as erythema and induration, indicating prior exposure to Mycobacterium tuberculosis or related mycobacteria. The test offered a means to identify individuals at risk for tuberculosis but suffered from limitations, including cross-reactivity with non-tuberculous mycobacteria and prior Bacillus Calmette–Guérin (BCG) vaccination, as well as variability in administration and interpretation.

Because of these drawbacks, the Pirquet test was gradually replaced by the Mantoux test, which uses an intradermal injection of tuberculin, and by later immunodiagnostic methods. Today, the Pirquet test is primarily of historical interest, illustrating early approaches to cutaneous testing and the evolution of understanding about delayed-type hypersensitivity and tuberculosis diagnostics. See also Mantoux test and tuberculosis.