The hook effect or the prozone effect is an immunologic phenomenon whereby the effectiveness of antibodies to form immune complexes is sometimes impaired when concentrations of an antibody or an antigen are very high.Furthermore, what causes Prozone phenomenon?
Prozone phenomenon is a false negative response resulting from high antibody titer which interferes with formation of antigen- antibody lattice, necessary to visualize a positive flocculation test. The prozone phenomenon is attaining importance because of increasing prevalence of Acquired immune deficiency syndrome.
Likewise, what is Prozone and Postzone? The prozone reaction refers to the absence of antibody-antigen precipitation in the presence of antibody excess. Since the authors refer to situations of antigen excess, the term prozone cannot correctly be used. Instead, absence of precipitation with excess antigen is described as the postzone phenomenon.
In respect to this, how can Prozone phenomenon be overcome?
It can be overcome by appropriate dilution and titration of antisera. We have observed that by simply washing the RBCs once more after the antiglobulin phase the prozone phenomenon is elimi- nated, and the strength of agglutination of RBCs (i.e., the sensitivity of the test) is con- siderably increased.
What is antigen excess?
Antigen excess (also known as “prozone” or “hook effect”) occurs when antigen is present in such high levels that it limits the antigen-antibody crosslinking, resulting in the formation of smaller immune complexes causing immunoassays to underestimate high concentrations of protein (see figure below)
What is Zone phenomenon?
Definition of zone phenomenon. : the occurrence of prozones in antibody-antigen mixtures.What is a Precipitin line?
Antibody and antigen samples diffuse toward each other from wells made in agar. A precipitin line will form wherever a zone of equivalence exists between a complementary antibody and antigen (i). In panels ii–v, a single antiserum is used to give information about the relationship between test antigens.What is the zone of equivalence?
Definition of equivalence zone. : the part of the range of possible proportions of interacting antibody and antigen in which neither or but small traces of both remain uncombined in the medium.What is Reagin antibody?
Reagin, also called homocytotropic antibody, or prausnitz-küstner antibody, type of antibody found in the serum and skin of allergically hypersensitive persons and in smaller amounts in the serum of normally sensitive persons. Most reaginic antibodies are the immunoglobulin E (IgE) fraction in the blood.What is the hook effect in prolactin?
The "hook effect": In patients with very large prolactinomas, the initial prolactin level may be read erroneously as normal or only mildly elevated. In such patients, it is important to confirm that the laboratory performed multiple dilutions of the blood sample to avoid this error known as the "hook effect".What is Prozone analysis?
Prozone provides the world's leading football performance analysis service. Their technology offers real-time, post-match and opposition analysis, and is used by clubs throughout the UK, USA, Europe and the Middle East.What is Anamnestic reaction?
Definition of anamnestic reaction. : renewed rapid production of an antibody following second or later contact with the provoking antigen or with related antigens.What causes hook effect?
There are versions of the hook effect with excess antibodies and versions with excess antigens. The phenomenon is caused by very high concentrations of a particular analyte or antibody and is most prevalent in one-step (sandwich) immunoassays. 
