Achieving Calibration Cost Savings Through Data Analysis

Air displacement type pipettes have been used effectively at the Savannah River Site (SRS) since the mid-1980's when they replaced expensive glass micro-liter pipettes. A paper presented at the 1987 INMM Annual Meeting by John P. Clark detailed the implementation at SRS.1 At that time, calibration frequency and required documentation were established according to regulatory and standard practice requirements. Pipettes are still being used at SRS in compliance with NQA-1-12, \"Control of Measuring and Test Equipment (M&TE)\" requirements, which includes defined calibration intervals and 5-year calibration record retention. A recent analysis of the pipette calibration historical data indicated that pipettes were rarely out of calibration when they were checked. In other words, calibration checks were being performed too frequently. As a result, pipette calibration frequencies were decreased, with the potential accompanying annual cost savings of over $30,000 in reduced labor and materials. Concurrently, the number of calibration check replicates was increased to prevent statistical errors in calibration check decision making. The benefits derived in the pipette calibration example are applicable to any M&TE where calibration history data are maintained and where analysis indicates excessive calibration checks. Details of the data analysis and cost savings are presented in the paper.