Prausnitz-Küstner test
Encyclopedia
The Prausnitz-Küstner test (PK test, Prausnitz-Küstner reaction) is an immunologic
Immunology
Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...

 test formerly used by physicians to determine if a patient has an allergic reaction to a specific antigen
Antigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

. The test has been replaced by the safer skin prick test
Skin allergy test
Skin allergy testing is a method for medical diagnosis of allergies that attempts to provoke a small, controlled, allergic response. -Process:A microscopic amount of an allergen is introduced to a patient's skin by various means:...

. The PK test involves transferring serum
Blood serum
In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...

 from the test subject to another healthy person, essentially using the second person as a mixing vessel for antibodies and antigen. This is a pathway for transmission of blood-borne diseases like Creutzfeldt–Jakob disease, AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

, and others, which is why the test is no longer recommended.

Procedure

Serum, suspected to contain IgE
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...

 antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

, is drawn from the allergic (atopic
Atopy
Atopy or atopic syndrome is a predisposition toward developing certain allergic hypersensitivity reactions.Atopy may have a hereditary component, although contact with the allergen must occur before the hypersensitivity reaction can develop ....

) patient. This serum is injected intradermally into a non-allergic person. The suspected antigens are then intradermally injected into the non-allergic person 24–48 hours later. If the person being tested for an allergy has made antibodies for the antigen, this will cause a local reaction in the non-allergic person when the antibodies mix with the antigen. This demonstrates a type I hypersensitivity
Type I hypersensitivity
Type I hypersensitivity is an allergic reaction provoked by reexposure to a specific type of antigen referred to as an allergen, or to a nonimmunologic stimulus like cold weather or exercise...

 reaction, and the allergic reaction to the injected antigen is confirmed for the patient being tested. A positive PK test usually appears as a wheal and flare.

Development

The test was developed by Otto Prausnitz
Otto Prausnitz
Otto Carl Willy Prausnitz , also known as Carl Prausnitz-Giles, was a German physician, bacteriologist, and hygienist who developed the Prausnitz-Küstner test with Heinz Küstner. Prausnitz was a student of Richard Pfeiffer, and is considered a pioneer of bacteriology and immunology...

 and Heinz Küstner
Heinz Küstner
Heinz Küstner was a German gynecologist and obstetrician who helped develop the Prausnitz-Küstner test while an assistant of Otto Prausnitz.-References:...

. The first PK test occurred in 1921 when Prausnitz injected Küstner's serum into his abdominal skin. Küstner had previously noted that he developed allergic symptoms after eating fish. After eating some fish, Prausnitz's skin became hot, red, and swollen at the site of the serum injection, confirming their hypothesis that Küstner was allergic to fish.

Reversed PK test

A reversed Prausnitz-Küstner test involves injecting antibodies into the skin of a person who already has the antigen. A wheal and flare in the skin also demonstrates a positive reverse PK test.

External links

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