The hook effect or the prozone effect is a type of interference which plagues certain immunoassays and nephelometric assays, resulting in false negatives or . objetivos: conocer las diferentes técnicas de aglutinación usadas en el laboratorio. adquirir habilidad y destrezas en las técnicas de. Prozone effect: No prozone effect was detected upon mg/dL. 4. . Efecto prozona: No se observa efecto prozona hasta valores de
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The hook effect or the prozone effect is a type of interference which plagues certain immunoassays and nephelometric assaysresulting in false negatives or inaccurately low results.
Term Bank – efecto prozona – Spanish English Dictionary
Other common prozonx of interference include antibody interference, cross-reactivity and signal interference. The phenomenon is caused by very high concentrations of a particular analyte or antibody and is most prevalent in one-step sandwich immunoassays. In an agglutination test, a person’s serum which contains antibodies is added to a test tubewhich contains a particular antigen. If the antibodies agglutinate with the antigen to form immune complexesthen the test is interpreted as positive.
However, if too many antibodies are present that can bind to the antigen, then the antigenic sites are coated by antibodies, and few or no antibodies directed toward the pathogen are able to bind more than one antigenic particle. Because no agglutination occurs, the test is interpreted as negative.
In this case, the result is a false negative. The range of relatively high antibody concentrations within which no reaction occurs is called the prozone. The effect can also occur because of antigen excess, when both the capture and detection antibodies become saturated by the high analyte concentration.
In this case, no sandwich can be formed by the capturing antibody, the antigen and the detection antibody. In this case, free antigen is in competition with captured antigen for detection antibody binding.
Examples include high levels of syphilis antibodies in HIV patients or high levels of cryptococcal antigen leading to false negative tests in undiluted samples. The serological test is mainly seen in the precipitation reaction.
The antibody that fails to react is known as the proona antibody and prevents the precipitating antibody from binding to the antigens. Thus the proper precipitation reaction does not take place.
However, when the serum is diluted, the blocking antibody is as well and its concentration decreases enough for the proper precipitation reaction to occur.
From Wikipedia, the free encyclopedia. Retrieved 3 February The Clinical Biochemist Reviews. Has its time arrived?