Use of Automation and Process Improvement to Achieve a Six Sigma Level of Nonanalytic Quality

Background: Clinical laboratories have focused on quality for more than 60 years. While analytic quality is considered excellent in most laboratories, nonanalytic quality is an area for focused improvement. One of our quality metrics, lost samples, has been tracked continuously for 25 years and has demonstrated steady improvement. Nonanalytic processes have become highly automated within our organization, which, we believe, was a major factor in reducing lost samples. We have also implemented numerous behavioral controls and completed many process reengineering projects that have had a demonstrable effect on lost sample rates. Our objective in this study was to determine the overall contributions of our error-proofing methods to reducing lost samples.

Methods: Using data spanning 25 years, we plotted the correlation between lost samples and the implementation dates for 8 major phases of automation along with 16 process improvements and engineering controls.

Results: The lost sample rate decreased nearly 100-fold. In Six Sigma terms, the 12-month moving average for lost samples currently hovers around 5.85-sigma, with several months at or better than 6-sigma. While implementation of process improvements, engineering controls, and automation all contributed to the reduction, automation was the most significant contributor.

Conclusions: The custom automation in use by our laboratory has led to improved nonanalytic quality. Although this level of automation might not be possible for all laboratories, our description of 16 behavior and engineering controls may be useful to other laboratories seeking to design high-quality nonanalytic processes.