What causes Prozone phenomenon?

Asked By: Rafika Dobrotvortsev | Last Updated: 7th April, 2020
Category: medical health medical tests
4/5 (88 Views . 28 Votes)
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.

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Keeping this in view, 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.

Also, 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.

Just so, what does Prozone effect mean?

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.

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)

13 Related Question Answers Found

What is Zone phenomenon?

Definition of zone phenomenon. : the occurrence of prozones in antibody-antigen mixtures.

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 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.

How do you test a hook effect?


How can you tell if you're experiencing the hook effect?
  1. Collect your urine in a cup.
  2. Dilute your urine with an equal quantity of water.
  3. Re-take a pregnancy test using the diluted urine.
  4. If you are experiencing the hook effect, the pregnancy test using diluted urine will be darker.

How common is the hook effect?

One explanation for a false negative pregnancy test is what's called the hook effect. It's not common but sometimes this effect leads to urine and blood tests giving the wrong result. This error might happen even after you've had one positive pregnancy test and test again a couple days later.

How common is the hook effect with twins?

This is called the 'hook effect'. It's more likely to occur in cases of twins or triplets, because the level of pregnancy hormone is so much higher. The hook effect in itself is pretty rare, but there are other reasons for producing a false negative. The most common reason for a false negative is testing too early.

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 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.