Change In Calibration Certificate Format – Removal Of NIST Number

Many customers will soon see a change in how the gauging and metrology industry references the N.I.S.T. number on calibration certificates. NIST is the acronym for National Institute of Standards and Technology.

NIST, A2LA, and many auditors are REQUIRING that we no longer list the NIST test report number on calibration certificates. The NIST number would typically change depending on the type of master used for calibration as well as each time the calibration masters were calibrated at NIST.

Thread Check Inc. is substituting the NIST number with the statement “ ….traceable to SI units through NIST”. This change has already taken place with many of our certificates of compliance and accuracy forms. SI is defined as System International

Many customers will be asking about this missing NIST number on their certificates. We are referring them to A2LA document P102-A2LA policy on Measurement Traceability available at and the NIST policy on traceability located at

Please note that Thread Check Inc is not A2LA accredited.

Please contact Thread Check Inc with questions or comments regarding this topic

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