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<span style="font-size:90%">Moew correctly the "prozone-like" or "postzone" phenomenon*  is a very rare, but recognised effect that causes false negative results of tests.  
<span style="font-size:90%">More correctly the "prozone-like" or "postzone" phenomenon*  is a very rare, but recognised effect that causes false negative results of tests.  


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<span style="font-size:90%">Most often the prozone effect is seen with HRP2 antigens. This effect means that where these is a '''very high parasitaemia''' (causing excess HRP2 antigen to be present) test can appear negative. It is thought that the presence of excess antigen means that the formation of appropriate antibody-antigen complexes is prevented so that the test does not function correctly.</br></br>*'''Note''' the term postzone effect is preferred in this context as prozone refers to excess antibody, while postzone refers to excess antigen as in this case.</span>
<span style="font-size:90%">Most often the prozone-like effect is seen with HRP2 antigens. This effect means that where these is a '''very high parasitaemia''' (causing excess HRP2 antigen to be present) test can appear negative. It is thought that the presence of excess antigen means that the formation of appropriate antibody-antigen complexes is prevented so that the test does not function correctly.</br></br>*'''Note''' the term postzone effect is preferred in this context as prozone refers to excess antibody, while postzone refers to excess antigen as in this case.</span>

Latest revision as of 10:25, 17 December 2024


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The prozone-like (postzone) phenomenon


More correctly the "prozone-like" or "postzone" phenomenon* is a very rare, but recognised effect that causes false negative results of tests.


Most often the prozone-like effect is seen with HRP2 antigens. This effect means that where these is a very high parasitaemia (causing excess HRP2 antigen to be present) test can appear negative. It is thought that the presence of excess antigen means that the formation of appropriate antibody-antigen complexes is prevented so that the test does not function correctly.

*Note the term postzone effect is preferred in this context as prozone refers to excess antibody, while postzone refers to excess antigen as in this case.