In order to use diatom testing there are some guidelines that scientists must follow. To get a more accurate result there has to be at least 20 diatoms in a 100 microliter sample. When dealing with testing on a human body having 5 complete diatoms from more than 2 different organs will also give a positive diagnosis.[1] Samples are taken from bone marrow, lung, spleen, liver, kidney, brain tissue, or from the area where the crime was discovered or occurred.[2]