What would you consider Negative re-assurance to include. How would it be expressed. As for the Notes the Lab usually sends with the Results obtained from Assays, the Lab would not know the exact protocol QA used by NOT and would note on every sample submitted particular observations and methodologies etc.. Just part of the security of data needed by Noront (any company submitting core for assaying) to determine the accuracy of assay results. If there are discrepancies Noront would learn that when comparing Repeat/Duplicates and Blanks etc. and would then chooses what to make of the Assay results returned from the Lab. The Assay Notes would be of help to Noront in this as well. However, I do not understand what you are suggesting with respect to Negative Re-Assurance. Any help on that is appreciated. Old Joe