While performing a Fluorospot assay, generally there should not be a situation where non-specific spots are observed. However, after performing the experiment multiple times by multiple people in our lab we observe occurance of non-specific spots with the same cytokine kit. Where one could have numerous reasons why a spot occurs in wells with cells added to them, it is quite confusing to reason out why the spots appear in wells where there were no cells at all (Cell Control) but just the media. Therefore, for this particular cytokine kit both the Cell control and Stimulant Control with cells shows similar spots. Is there anyone who has experienced a similar problem and can explain what actually goes wrong here, what might be its probable reason and the measures one should take to avoid this?