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Standard Interpretation

SIR #: 125
Standard: 2003 NELAC
Section: (h)


In the analysis of samples for pH...our buffer range is 2 through 12. Does that mean we need to flag any values outside this calibration range? Is "J" appropriate? or a flag identified as "out side calibration range"?

FYI - our analyst found a reference that states that negative values for pH are possible...and she actually got a sample like that last week from mine waste.


(Quality Systems Expert Committee and NELAP AC, 10-4-14)

The result must be qualified to indicate that it is outside the calibration range.

The use of flags to qualify data is dependent on the client requirements and state regulatory requirements. The committee cannot comment on the specific qualifier that is appropriate to use, as the use of qualifiers varies.