900.2(xx) Traceable to a national standard means an instrument is calibrated at either the National Institute of Standards and Technology (NIST) or at a calibration laboratory that participates in a proficiency program with NIST at least once every 2 years and the results of the proficiency test conducted within 24 months of calibration show agreement within +/- 3 percent of the national standard in the mammography energy range.
- If a calibration laboratory that failed its last test has carried out corrective actions that it believes will now allow it to pass, will any of the air kerma instrument calibrations provided by the laboratory during the re-testing process be acceptable toward meeting the MQSA requirement?
- If NIST is unable, for any reason, to conduct a proficiency test for a calibration laboratory before the laboratory's 2 year expiration date, are the laboratory's calibrations provided between the expiration date and the date of passing the proficiency test acceptable?
- What if the laboratory continues to provide mammography calibration services during these 60 days, but then is informed that it has failed the proficiency test. Will the physicists who had their instruments calibrated during that period have to have them recalibrated? Will they have to resurvey any facilities that they might have surveyed during that period?
- A physicist utilizes a calibration laboratory after it has been notified by the National Institute of Standards and Technology (NIST) that it has failed its latest proficiency test. Can those instruments calibrated by the laboratory be used for MQSA evaluations?