Preanalytical errors in a satellite stat laboratory: A Six Sigma analysis of seven years’ data

Background: There have been few reports regarding the frequency and types of preanalytical errors in stat laboratories, in particular those occurring in the satellite laboratory setting. The impact of this error type on laboratory performance in this environment is largely unknown. We assessed the performance of a stat laboratory serving a population of predominantly elderly patients with suspected or established diagnoses of cancer using Six Sigma methodology and compared the results to previous work on this subject. Methods: We performed an observational retrospective study using data from the period 2013–2020. The clinical setting was a satellite laboratory supporting an outpatient medical clinic. The type and frequency of each type of preanalytical error were compiled and were used to derive the quarterly error rate. Overall and quarterly performance were calculated using Six Sigma methodology. Results: During the study period 1314 preanalytical errors were identified from 247,271 laboratory tests (0.5% of total test volume). There was a steady decrease in the error rate over the course of the study period, ranging from 1.4% in 2013 to 0.14% in 2020, despite a 290% increase in quarterly test volume during this period. The most common error types encountered were order error, hemolysis, collection error, and lab accident. Conclusion: 1) The overall performance of a satellite laboratory with a stat testing menu is comparable to hospital-based laboratory stat testing. 2) The most frequent error types encountered in satellite laboratory stat testing differ from those found in hospital-based laboratories. 3) There was an overall improvement in laboratory performance based on Six Sigma methodology.