Quality assurance / Quality Control and external validation / Quality Management

Quality results are the desired outputs of any microbiology laboratory. The results generated should be accurate (i.e. reflecting the true situation) and precise (i.e. reproducible). The microbiology lab should correctly identify the organisms and correctly identify the antimicrobial susceptibility profile of that organism. Quality management is the holistic process that ensures quality results and can be defined as the “coordinated activities that direct and control laboratory activities with regards to quality”.

Quality management can be divided into two parts:

1. Internal quality control (IQA): this covers all routine, control and test procedures that a laboratory undertakes and involves the monitoring and documentation of all procedures to ensure quality results. Aspects of routine laboratory operations that should be monitored as part of IQA are:

• The quality of reagents: proper storage, pH, reagent effectiveness, observed expiry dates.

• The functioning of equipment: regular manufacturer recommended maintenance and proper calibration.

• Precision and accuracy of the test method: use of appropriate controls to ensure accurate results.

• The qualifications and performance of the staff performing the tests.

• The accuracy of the results being disseminated: proper recording and interpretation of results into databases or reports.

2. External quality control (EQA): this is an objective assessment conducted by an external agency to evaluate the performance of a laboratory. Typically this involves comparing the test outcomes of the laboratory being assessed against the test outcomes of a second or reference laboratory.

Ideally the laboratory should be enrolled in an external quality assurance (EQA) scheme for independent verification of the labs proficiency and staff competence in performing bacterial culture, identification and AST tests. Microbiology and AST EQA schemes are offered by agencies such as the European Centre for Disease control (ECDC), United Kingdom National External Quality Assurance Scheme (UK NEQAS), WHO AFRO organized by the National Institute for Communicable Diseases (NICD), South Africa. Countries may have local EQA schemes that are more practical and affordable. Alternatives to the formal EQA schemes are conducting inter-laboratory comparisons, re-testing of results with a reference lab or having an on-site evaluation to verify test procedures.