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Standard Interpretation

Standard: 2003 NELAC
Link to relevant standard


This section of the standard talks about observation, data and calculations recorded at the time they are made. Currently our lab has a policy in place to mark the preservation checks for each sample separately. Example a specific sample has a pH of less 2 and chlorine result of zero. Would it be sufficient to document the pH and chlorine checks by a general statement for example "all samples extracted in the batch had a pH less than 2 and chlorine result of zero"?


(NELAP Board, 12-19-08)

No. requires observations to be recorded at the time they are made. requires date/time of sampling to be recorded, so as to demonstrate compliance with holding times. states the laboratory shall implement procedures for checking chemical preservation prior to or during sample preparation or analysis.

3(b) requires the results of these checks to be recorded. (2) (iv) requires comments resulting from inspection for sample rejection to be linked to the laboratory ID code.

So, the lab could, for example, use a check box on a sample receipt form to indicate a sample's preservation was checked and the result was less than 2 and chlorine was zero as long as the observation was unequivocally linked to each sample checked. The lab could not simply preprint this statement on an analytical report or document preservation after-the-fact in an extraction log because doing so would not comply with requirements to record observations at the time they are made and link the results of preservation checks unequivocally with sample identification numbers.