- “A” Confirmation Procedure  for Threshold Substances  For Threshold Substances , Adverse Analytical Finding  or Atypical Finding  decisions for the “A” Sample  shall be based on the confirmed identification (in accordance with the TD IDCR, applicable to Confirmation Procedures  based on chromatography -mass spectrometry) of the Threshold Substance  and/or its  Metabolite(s)  or Marker(s)  and their quantitative determ ination in the Sample  at a level exceeding the value of the relevant Decision Limit , which is specified in the TD DL or other applicable Technical Document (s) (e.g.