MU); o Assessment of the existence of significant data or information that would cast doubt on or refute the Laboratory  findings ;  [Comment: The Laboratory  should consider the prevailing scientific knowledge regarding, for example, the possibility of Sample or Aliquot  contamination, the presence of analytical artifacts, the possible natural occurrence of the Analyte at low concentrations, microbial or chemical degradation, the detection of Metabolites which may be common to non -prohibited substances or the absence  of characteristic Phase -I or Phase -II Metabolites.]