The field of forensic science deals with the analysis of a large number of evidence (namely biological, chemical physical and other materials respectively) via application of various methods ranging from preliminary to confirmatory testing. The use of these methods may sometimes poses serious challenges in front of forensic scientists while analyzing these evidence in the laboratory which leads to non-detectability of the desired substance and thereby incompetency in reporting the results. The present article is a short review highlighted the common reasons responsible for incompetency in reporting of such cases along with some suggestive measures.