A primer on patient-based quality control techniques

Background: Patient-based Quality Control techniques have been described for more than fifty years and have been widely used routinely in hematology for forty. However, because of practical issues they have not been widely utilised in clinical chemistry laboratories. But recently because of the availability of middleware and a greater appreciation of the benefits of these processes there has been a willingness to investigate their use as a QC tool. Content: This Review describes the development of various patient-based quality control techniques from the earliest Average of Normals approach including the Moving Average, Moving Median and Moving Sum of Outliers. Variations such as weighting, transformation and annealing are discussed. Integrating patient-based QC and conventional QC is discussed as the problem of sub-populations. Summary: Patient-based QC methods will become more widespread as their benefits are more fully understood and middleware becomes available that allows laboratories to implement these techniques with their patient populations.