other reasons of false negatives with ELISA lab test?

[freakingout2012]

is it only when done too early? are there any other cases, such as labs messing up, or whatever?

thanks for your comments

[freakingout2012]

sorry to wrongly interpret the rules of the forum. i promise no more questions.
although related to my situation, i thought im asking something that perhaps interest some other readers of forum. with my last question :
-- Im not questioning results
-- Im not questioning expert opinion
-- excessive posting is subjective.
i don't intend to bother. i like the forum and think service is wonderful
thanks for your help and support in last few weeks.  it has been nightmare.
paz!

[Teak]

* Anyone who continues to post excessively, questioning a conclusively negative result or no-risk situation, will be subject to action by MedHelp. Conclusively negative results or a no-risk situation will be based upon the criteria established by MedHelp’s doctors. Action will be taken as follows:
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