Dick Test : Diagnosis-Benefits

 What Is Dick Test?

Dick test, technique of figuring out susceptibility to scarlet fever by using injection into the pores and skin of 0.1 cubic cm of scarlet fever toxin. A reddening of the pores and skin in an area over 10 mm (0.4 inch) in diameter inside approximately 24 hours suggests a lack of immunity to the sickness. The check evolved in 1924 with the aid of American physicians George Dick and Gladys Dick.

The Dick test is a laboratory test designed to indicate whether or not or now not a person is proof against (will not get) scarlet fever. Scarlet fever is an adolescence disorder. It derives its call from the flushed face, crimson rash and fever that it causes. The Dick test is named after George Dick and Gladys Dick, American bacteriologists who worked at the diagnosis and remedy of scarlet fever inside the Nineteen Twenties.The Dick test includes administering  distinct injections, one into every arm of a patient. In one arm, toxin (poison) taken from a lifestyle of scarlet fever microorganism is injected. In the alternative arm, neutralized toxin is injected to act as a control (a preferred of assessment). If the toxin causes redness, tenderness and swelling after 24 hours, the person is not proof against scarlet fever. The manager normally shows no swelling for comparison.

George and Gladys Dick obtained a British patent for their take in 1924 and a U.S. Patent in 1925. The patents had been for setting apart the streptococcus bacteria that causes scarlet fever and for the instruction of an antitoxin for its remedy. Armed with the check and the antitoxin, docs may want to diagnose and deal with the ailment a great deal extra effectively. This resulted in a decline in the variety of cases. Once antibiotics have become more broadly used, the incidence of scarlet fever has become pretty uncommon.

The Schick test, also known as the diphtheria immunity test, is a diagnostic test used to determine a person's immunity to diphtheria, a bacterial infection caused by Corynebacterium diphtheriae. This test was historically important before the widespread use of diphtheria vaccines.

Here's how the Schick test works:

  • Preparation: A small amount of diphtheria toxin is obtained and standardized. This toxin is inactivated, so it cannot cause the disease.

  • Test Administration: A small amount of the inactivated diphtheria toxin (the Schick test antigen) is injected intradermally (under the skin) on the forearm.

  • Observation: The area where the test antigen was injected is closely monitored over the next 48 to 72 hours.

  • Results: Depending on the individual's immunity to diphtheria, one of the following reactions can occur:

    • Positive Reaction: If the individual has not been previously exposed to diphtheria or has not developed immunity through vaccination, they will exhibit a localized skin reaction at the injection site. This reaction typically consists of redness, swelling, and sometimes blistering.

    • Negative Reaction: If the individual has pre-existing immunity to diphtheria due to prior infection or vaccination, they will not show a significant skin reaction, indicating their protection against diphtheria.

The Schick test was historically used to identify individuals who were susceptible to diphtheria and required vaccination. However, it has largely been replaced by routine childhood immunization programs that include diphtheria toxoid-containing vaccines. These vaccines stimulate the immune system to produce antibodies against diphtheria without the need for the Schick test.

It's worth noting that the Schick test is not commonly performed today, as the focus has shifted towards vaccination and monitoring vaccine coverage to prevent diphtheria outbreaks.


The Schick test, though largely replaced by routine vaccination programs, had several benefits and purposes in the past:

  • Identification of Susceptibility: The primary benefit of the Schick test was to identify individuals who were susceptible to diphtheria. By administering the test antigen, medical professionals could determine if a person had pre-existing immunity to diphtheria or if they were susceptible to the disease.

  • Targeted Vaccination: For individuals who tested negative (indicating susceptibility), the Schick test provided a basis for recommending diphtheria vaccination. This allowed for targeted vaccination efforts, ensuring that those most at risk received the vaccine.

  • Preventing Outbreaks: The Schick test could be used on a larger scale to assess the susceptibility of specific populations or communities. This information could guide public health officials in implementing vaccination campaigns to prevent diphtheria outbreaks in areas with low immunity.

  • Research and Surveillance: The test provided valuable data on the prevalence of diphtheria immunity in a population. This information could be used for epidemiological research and surveillance of diphtheria incidence.

  • Safety Assurance: Before widespread vaccination programs, the Schick test helped ensure that only individuals lacking immunity received the vaccine. This minimized the risk of adverse reactions in individuals who were already protected.

It's important to note that while the Schick test had these benefits, it also had limitations and drawbacks. It required skilled healthcare professionals to administer and interpret the test accurately, and it could sometimes yield false-positive or false-negative results. Moreover, the Schick test is not used as widely today because vaccination programs have become the primary means of preventing diphtheria, and diphtheria outbreaks are relatively rare in regions with high vaccine coverage.

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