Positive shick's test indicates that person is ?

Ans. is 'c' i.e., Susceptible to diphtheria Shick test . Shick test is no longer in use. It was used for the susceptibility of for diphtheria. . It was an intradermal test, in which after intradermal injections of diphtheria toxin in one forearm (usually left) and toxoid in other forearm two readings were taken one at 24-48 hrs and second at 5-7 days. . Interpretation of the test : - Reaction in control arm indicates hypersensitivity - Reaction in test arm : at 24 - 48 hrs --> Hypersensitivity at 5 - 7 days --> Susceptibility Type of reaction Observation inference Negative reaction No reaction on either arm, (toxin neutralized by circulating antitoxin) No susceptibility No hypersensitivity Positive reaction No reaction on control arm, Circumscribed erythematous reaction caused by toxin on the test arm that persists. No hypersensitivity Susceptibility present Pseudoreaction Diffuse erythematous reaction on both areas, appearing with in 24 hrs and fading by 4 days. Combined reaction Both areas initially show Hypersensitivity present pseudoreaction followed by positive reaction on test arm Susceptibility present