3.3 Quality procedures to identify and minimise errors

Several terms are used to describe different aspects of laboratory quality: quality indicators (QIs), quality controls (QCs), quality assurance (QA), and quality management system (QMS). These terms are explained in Figure 4.

Figure 4 The organisation of quality procedures in quality management systems.

Show description|Hide description

A Venn diagram of how quality procedures are organised in a quality management system:

• QMS: A set of activities to develop, document and implement continual improvement of the overall process through regular management reviews, and corrective and preventive actions.
• QA (located inside QMS): A set of activities to monitor the overall testing process (which includes handling, processing and analysing samples) and using QCs and QIs over time to provide confidence.
• QC (located inside QA): Monitoring of each individual test or process to ensure that all quality requirements are being met.
• QI (also located inside QA):Observations, statistics or data used to determine the performance of a process.

Figure 4 The organisation of quality procedures in quality management systems.

QIs are observations, statistics or data that prove the organisation is meeting its intentions, for example, that its blood culture contamination rate is below 3%. QCs monitor whether the test performs as expected – for example, using a control organism to ensure that reagents or media give the expected result or growth. QA looks at the overall process to confirm that the requirement for quality is fulfilled. This involves tracking QCs and QIs and analysing trends. In the analytical phase, for example, QA ensures that all the relevant SOPs are in place, staff have been trained, the necessary QC checks are being done, and the results are recorded and reported correctly for that process.

Finally, a laboratory QMS is a systematic integrated set of activities to establish and control all processes in the workflow path. The founding principle of a QMS is continual improvement. It manages resources, conducts evaluations and makes continual improvements to ensure consistent quality results. A good QMS ensures that when errors are detected, both preventive and corrective measures are implemented to improve a process (WHO, 2011a; Carey et al., 2018).