- “A” Confirmation  Procedure  for Non-Threshold Substances  For Non-Threshold Substances  without Minimum Reporting Level s, Adverse Analytical Finding  or Atypical Finding  decisions for the “A” Sample  shall be based on the identification of the Non-Threshold Substance  or its characteristic Metabolite (s) or Marker (s), as applicable, in compliance with the TD IDCR and/or other relevant Technical Document  (e.g.