Dick test

The Dick test is a laboratory test designed to indicate whether or not a person is immune to (will not get) scarlet fever. Scarlet fever is a childhood disease. It derives its name from the flushed face, red rash and fever that it causes. The Dick test is named after George Dick and Gladys Dick, American bacteriologists who worked on the diagnosis and treatment of scarlet fever in the 1920s.

The Dick test involves administering two different injections, one into each arm of a patient. In one arm, toxin (poison) taken from a culture of scarlet fever bacteria is injected. In the other arm, neutralized toxin is injected to act as a control (a standard of comparison). If the toxin causes redness, tenderness and swelling after 24 hours, the person is not immune to scarlet fever. The control normally shows no swelling for comparison.

George and Gladys Dick obtained a British patent for their test in 1924 and a U.S. patent in 1925. The patents were for isolating the streptococcus bacteria that causes scarlet fever and for the preparation of an antitoxin for its treatment. Armed with the test and the antitoxin, doctors could diagnose and treat the disease much more efficiently. This resulted in a decline in the number of cases. Once antibiotics became more widely used, the incidence of scarlet fever became fairly uncommon.