External Quality Assessment (EQA) / Proficiency Testing (PT) allows for a comparison of a laboratory’s testing procedures to other laboratories across the world. Comparisons can be made to a peer group of laboratories or to a reference laboratory.
EQA involves running blind patient-like samples, comparing your results to peer results, in order to retrospectively monitor the accuracy of reporting. EQA samples should be treated as if they were a patient sample and therefore must be run by personnel who would normally use the device. This provides confidence in the reliability of patient test results.
EQA provides assurance to both staff and customers that testing taking place at your laboratory provides accurate and reliable results. Problems can be identified early on and corrective action can be untaken. The reliability of methods, materials, and equipment can be evaluated and training can be developed and its impact monitored.
Large laboratory groups can compare their performance with sites across their group, ensuring accuracy and consistency no matter where testing takes place.
EQA participation is often a requirement for accreditation, gaining accreditation alone has a host of benefits, not least an increased confidence in results from customers, current and potential.
Read more about accreditation: ‘The Importance of Meeting ISO 15189 Requirements’.
Point of care testing (POCT) refers to testing that is performed near or at the site of a patient with the result leading to a possible change in the care of the patient. The popularity and demand for POCT has recently seen rapid growth, this comes from the advantages including the added convenience of being able to obtain a rapid result at the patient’s bedside, thus allowing immediate action, saving time and improving the potential outcome for the patient.
Although there are many benefits of using POCT devices in terms of their convenience, these benefits are only true if the results produced are both accurate and reliable. Ensuring accuracy and reliability is the primary responsibility of Quality Control.
EQA is strongly recommended for all point of care devices and is recommended by ISO 22870, which providesspecific requirements applicable to point-of-care testing and is intended to be used in conjunction with ISO 15189.
There are many External Quality Control schemes that come in different varieties. EQA schemes can be mandatory, required either by accreditation or law. Others are voluntary and carried out by laboratories who want to ensure that they are carrying out accurate testing and improve the quality of the lab’s performance .
A good EQA scheme should offer:
EQA is a great tool for comparing against a peer group and maintaining an effective QC strategy, however, it has its limitations.
EQA / PT alone cannot provide a complete evaluation alone; it is important to also run third party controls regularly. You can find out about the importance of third party controls here.
EQA results can also be affected by variables not relating to patient samples, including preparation, clerical functions, matrix effects, and selection of method. The errors can appear to be a downside to EQA but it can be used as a way to evaluate staff performance as well as assay performance.
If possible, every laboratory should participate in an EQA scheme that covers all testing procedures. Laboratories need to develop a management process with the objective to assure that EQA samples are treated appropriately and in the same manner. This includes, sample handling, sample analysis, record keeping, investigating deficiencies, taking corrective actions, and communicating results with laboratory staff and management.
Problems at any stage of sample analysis can cause errors, when an error does happen, all elements of the process need to be checked. Some examples of errors:
• Incorrect sample handling during preparation, shipping or storage
• Improper storage
• The material has expired
• An error in manufacturing
• Instrument, calibration or reagent defects
• Staff competency
• Matrix effects
• Incorrect analysis method
• Report misinterpretation
• Clerical or transcription errors
• Failure to take corrective action
• Where possible, all laboratories should participate in an EQA scheme for all tests that they perform.
• EQA samples should be treated in the same way as a patient sample, using the same procedures, instruments, methods, and staff who normally perform the testing.
• EQA provides valuable resources and data to effectively maintain accurate and reliable results and should be seen as educational.
Randox offers RIQAS, the largest EQA scheme in the world with over 45,000 participants across 133 countries, offering 33 consolidated programmes. Randox also offers a range of over 90 molecular programmes for infectious disease testing with Quality Control for Molecular Diseases (QCMD).
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