Proficiency testing

Frequently asked questions

What is proficiency testing and why does the Diagnostic Accreditation Program (DAP) require it in a medical laboratory?

In laboratory medicine, proficiency testing (PT) is a way of evaluating how well a medical laboratory performs a particular test in comparison to another laboratory using pre-established criteria. For example, to determine if laboratory A is accurately measuring blood glucose, it requests a pre-measured sample from laboratory B, runs that sample through its systems, and compares the results. If the measurement obtained by laboratory A is the same as the measurement obtained by laboratory B, then laboratory A is performing its test correctly.

This is a simple example and, in today’s world, proficiency testing is a much more sophisticated and formalized operation, with pre-measured samples coming from commercial suppliers that specialize in providing samples and statistical analysis for PT. However, the principle is the same: by comparing results across laboratories, patients, customers and laboratories themselves can be confident in the quality of services offered.  

The DAP requires PT to protect patients and the public. PT is critical to evaluating the quality of test results produced by the medical laboratory. Without PT, medical laboratories might perform tests and release results without knowing they might be inaccurate. By requiring labs perform PT, the DAP enhances public safety and gives confidence to health-care providers using laboratory services in BC.

The DAP on-site assessments of medical laboratories occur once every four years. In between these on-site assessments, the DAP requires that laboratories perform PT for all applicable tests within their scope of accreditation, usually by working with a professional, third-party proficiency testing supplier.

The DAP requires laboratories participate in a minimum of two PT testing events (challenges) per year for each test within their scope of accreditation.  

Throughout the accreditation cycle the DAP receives and reviews copies of PT reports for each laboratory. Unacceptable PT results are flagged so the DAP can monitor that laboratories are submitting a PT Investigation Response Form for DAP reportable exceptions.

The laboratory investigates unacceptable PT results under the guidance of their medical director. If the unacceptable results meet the DAP reportable exceptions criteria the laboratory sends the DAP a PT 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 PT performance, the matter is referred to the DAP Committee for reconsideration of that medical laboratory’s accreditation award.