This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Prausnitz-kustner reaction is a 
Select and explain. 
A. Type I Hypersensitivity, B. Type II Hypersensitivity, C. Type III Hypersensitivity, D. Type IV Hypersensitivity
A: Type I Hypersensitivity
Answer: A: Type I Hypersensitivity 
Explanation: Prausnitz-Kustner test was formerly used to determine if a patient has an allergic reaction to a specific antigen. A patients serum is injected in healthy person skin and antigen was injected at same site 24 hours later.If the patient was sensitive it would trigger a type I reaction. <img class="fr-dib" style="width: 300px;" src=" /> Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 165