External quality assessment
In some jurisdictions, the terms "proficiency testing" and "external quality assessment" are used interchangeably. To maintain alignment with ISO/IEC 15189:2022, the DAP has adopted the term external quality assessment (EQA).
EQA evaluates how well a medical laboratory performs a particular test in comparison to another laboratory using pre-established criteria. It monitors performance in all phases of the testing cycle, including interpretation of results.
Why does the DAP require EQA in a medical laboratory?
As part of the laboratory quality management system, in conjunction with internal quality control, EQA is critical to evaluate the quality of test results produced by the medical laboratory. By requiring labs to perform EQA, the DAP gives confidence to health-care practitioners using laboratory services in BC and enhances public safety.
EQA is a sophisticated and formalized operation, with pre-measured samples coming from commercial suppliers that specialize in providing samples and statistical analysis for EQA. The principle is that by comparing results of the same sample across multiple laboratories using the same reagents and equipment, labs can verify performance against pre-established acceptance criteria. Patients, health-care practitioners and laboratories themselves can be confident in the quality of services offered.
The DAP on-site assessments of medical laboratories occur every two or four years, depending on the accreditation scheme. In between these on-site assessments, medical laboratories participate in a minimum of two EQA testing events (challenges) per year for each test within their scope of accreditation.
Throughout the accreditation cycle the DAP receives and reviews copies of EQA reports for each laboratory. Unacceptable EQA results are flagged so the DAP can monitor that laboratories are submitting an EQA Investigation Response Form for DAP reportable exceptions.
The laboratory investigates all unacceptable EQA results under the guidance of their medical director. If the unacceptable results meet the DAP reportable exceptions criteria, the laboratory sends the DAP an EQA Investigation Response Form which summarizes the investigation and corrective actions taken. If the results are not reportable to the DAP, the laboratory retains the investigation records as part of their quality management system records.
In cases where the medical laboratory demonstrates ongoing, unacceptable EQA performance, the matter is referred to the DAP Committee for reconsideration of that medical laboratory’s accreditation award.
Forms and resources
| Resource | Description | File type |
|---|---|---|
| Laboratory Medicine External Quality Assessment Manual | Describes the processes, forms, and requirements of EQA in accredited laboratory medicine facilities | PDF manual |
| Available EQA Providers | List of accredited and non-accredited EQA vendors | PDF list |
| Reportable Measurands by Service | Measurands that must be monitored by formal EQA programs and are reportable to the DAP | PDF list |
| EQA Investigation Response Form | Form to provide a summary the investigation of EQA exceptions to submit to DAP | PDF form |
| EQA Investigation: Sources of Error Form | Checklist to collate sources of errors | PDF checklist |