CHAPTER 3
Quality aspects of laboratory medicine
CHAPTER OUTLINE
INTRODUCTION
It was emphasized in Chapter 2 that every step in the process, from the ordering of the investigation, through collection of the specimen(s) required, their transport to the laboratory and analysis, to the delivery of a report to the clinician, is vital in ensuring that results of investigations are used appropriately. Interwoven throughout each step is the requirement to ensure the quality of the whole process. Chapter 2 has already discussed the need to minimize analytical variation through the use of processes to reduce imprecision and bias. The use of standard operating procedures has also been alluded to, but this chapter will expand on the use of laboratory standards to maintain quality.
WHAT IS QUALITY?
Quality is difficult to define, and may be considered to be ‘doing the right test, for the right patient, at the right time for the right reason’, but may equally be defined as ‘adhering to stringent processes in order to complete the task’. Ultimately, perhaps the question to ask is how to assess the quality of a laboratory service.
QUALITY STANDARDS
Quality assurance
Clinical biochemistry laboratories operate extensive quality assurance procedures to ensure that the results that they produce can be relied upon to support clinical decision-making. They include internal quality control (IQC) schemes, for example involving replicate analysis of clinical samples and the repeated analysis of reference samples of identical composition, and external quality assurance (EQA) schemes involving the analysis of identical samples by a large number of laboratories.
The measurement of IQC samples allows a prospective estimate of the precision of the analyses that are being performed. The frequency of measurement of such controls may depend upon each laboratory’s workload and the type of analysis undertaken. For example, it is not unusual to run quality control material at the start and the end of a sample batch measured by enzyme-linked immunosorbent assay (ELISA).
The measurement of EQA samples provides laboratories with a retrospective view of the accuracy of their measurements and the consistency of any bias that may be present. The data can be invaluable when troubleshooting possible assay problems, by allowing the laboratory to compare their result with both the reference value (if available) and the method-specific mean. The review and interpretation of EQA reports is an important skill for laboratory personnel to develop because of the variety of ways in which different EQA schemes choose to present their data. (Examples may be accessed via the website addresses of the various EQA providers included in Further reading, below.)
Not only the analysis itself, but also the interpretation of the result should be subjected to quality assurance: there exists a peer-reviewed EQA scheme for interpretative comments.
Reviewing quality assurance procedures is an essential part of the audit of laboratory performance (the assessment of overall performance with regard to the appropriateness of the use of tests, the interpretation of their results, adherence to standard procedures, cost-effectiveness etc.). Laboratory data should also be included in the medical audit, in which the effectiveness of all aspects of clinical care is examined. The ultimate test of the performance of laboratory data is provided by the clinical outcome when this has been determined, in whole or in part, by those data.
Regulation of laboratories
External regulation of laboratories has evolved over some time to include every aspect of the laboratory service. Independent regulatory bodies are empowered to award accredited status to laboratories meeting stringent standards and to fail to award or remove accreditation from laboratories which are found to have serious failings at inspection. Throughout the world, there are several organizations that fulfil this role: International Standards Organization (ISO), United Kingdom Accreditation Service (UKAS) and the Division of Laboratory Services and Standards in the USA, to name but a few. Their main aim is to ensure a laboratory’s quality and competence to perform specified tasks. It is important to note that all parts of the laboratory are inspected, including the environment in which the laboratory is based. Very dilapidated buildings (in which pathology departments are sometimes located) will be a cause of concern for the inspectors, as it may reflect the low priority given to laboratories within a wider healthcare setting, such as in a hospital.
Within the UK, for example, the current list of standards against which laboratories are judged comprises almost 60 pages. The broad areas covered are listed in Box 3.1. It is worth noting that the analytical process itself is just one out of eight categories examined by such an inspection.
Quality management systems
A system of ‘Quality Management’ is an all-encompassing term used to describe the steps a laboratory may take to maintain current procedures and to establish continual service improvement via quality objectives.
The majority of laboratories in the UK will have a designated Quality Manager, either exclusively within their own discipline or as part of a multidisciplinary team. The development of web-based document management systems (e.g. QPulse, i-Passport) has enabled laboratories to greatly improve document control and to track review dates, changes and the number of printed copies in circulation. Complete written procedures should be in place for all tasks performed in a laboratory. Manufacturers are obliged to publish ‘Instructions for Use’ with each reagent supplied that contains the majority of worthwhile data. These procedures, however, form only part of the process, as the essence of a quality management system is that it documents what should take place within the laboratory in its entirety. All members of laboratory staff should be familiar with the quality management system, understand the requirement for such a system and the need to maintain the documents within it. Indeed, it is the effective implementation of the system, and adherence to it, that is likely to lead to quality improvement. Monitoring the effectiveness of the system is achieved by audit (see below) and by reviewing processes in a regular basis.
Many laboratories try to minimize the amount of printed material generated, owing to ever greater space and storage constraints. Improved reliability of information technology and the need to minimize waste are also important driving factors towards operating a paperless Quality Management system.
Personnel
When contemplating quality, staffing issues may not immediately spring to mind. Staff are, however, the most valuable assets of any laboratory. Staff morale and continuing professional development play a vital role in a ‘good’ quality laboratory. Education and training of all levels of staff within the laboratory ensures that their knowledge and understanding of laboratory science is current and up-to-date. The competence of staff undertaking laboratory tasks should be documented and regularly reviewed. Formal individual review meetings are recommended to assess training needs and to promote further development.
