External Quality Assessment (EQA) in medical laboratories have evolved over the past 50 years to provide more sophisticated systems compared with the simple participant’s analytical performance evaluation of earlier years. There are clear distinctions between the proficiency testing programmes and the evolved External Quality Assurance Programs (EQAP). Not only do they provide participant performance evaluation including pre-analytical and post-analytical evaluation, but also method evaluation, and postmarketing vigilance. Education is pivotal in these programmes with training and help being provided. Programmes that do not include Quality Assurance as defined in EQAP will ultimately fail to improve quality, and laboratories should consider these elements in their choice of EQA provider. The key objective of EQA is continuous quality improvement within laboratory medicine, and EQA providers should therefore include quality improvement of programme design as an essential requirement of the service.
External Quality Assurance Program (EQAP) is an interlaboratory comparison designed and operated to assure one or more of the following aspects, which will be described in the following sections:
This is an evaluation of a participant’s measuring performance compared with other laboratories using the same methods. International and regional programmes can be used to assess one or more of the following:
- The quality of the analytical performance of the participant’s laboratory
- The state of the art of participating laboratories
- Intralaboratory variation
- Relationship between calibration procedures and analytical results
- Relationship between analytical procedures and results
- Relationship between commercial reagents and results
- Relationship between analytical instruments and results
- State-of-the-art values for concentration of the analytes
- Systematic deviations for the individual laboratory from state-of-the-art values or reference target values
A well-designed EQA Programme should provide information on most of the ten points.
Weqas easily fulfils these aims and offers its participants powerful statistical tools to identify and eliminate errors before the system is out of control. The linear panel of samples used in most Weqas Programmes allow the evaluation of accuracy, within run precision and between batch precision.
Weqas has interpretive programme for both Porphyrin and Immunoassay. In the Weqas Porphyrin Programme the analytical and interpretative elements are examined. The following is an example of the clinical information distributed together with an EQA sample:
A blind sample is distributed along with clinical information e.g. a urine sample with a total porphyrin concentration of 1400 nmol/L was distributed along with the following clinical information: “46 year old gentleman complaining of skin fragility and blistering lesions on the backs of his hands.”
The correct interpretation is given by an expert advisor and is made available to all participants along with a summary of the responses. Key phrases used by the expert are used to evaluate the responses.
Laboratories are recommended to use in vitro diagnostic devices (IVDs) according to the manufacturer’s instructions. To allow the assessment of accuracy, EQA evaluation requires the use of commutable material and sample material as close as possible to patient samples to minimise any matrix effect. By comparing a homogeneous group of users of the same IVD the method performance can be evaluated. This type of evaluation has proved to be particularly difficult in blood gas analysis due to the inherent instability of the patient sample. Over the last few years the Weqas Blood Gas Programme conducted studies to assess the performance of routine blood gas analyzers in the UK using a tonometered whole-blood material.
By using dedicated designs and samples, Weqas EQA programmes can be used for studying robustness of methods, sensitivity to interferences, linearity, recovery, specificity and also pre-analytical and post-analytical factors. Weqas Serum Chemistry and Weqas Lipid Programme are excellent examples of our commitment to programme design and programme improvement.
EQA Programmes play an important role in the continuous education of laboratory staff. Weqas plays a key role in Regional and National Audits and in promoting harmonization of results, e.g. HbA1c standardization. An annual scientific conference is hosed by Weqas covering topical, clinical and scientific issues, including EQA interpretation and problem solving. Presentations from our most recent Annual Conference are available from our Participant Zone/Education and Training page. Additionally, educational material is supplemented and available via Resources.
The primary intention of the activities of an EQAP in laboratory medicine shall be; To support quality improvement of the services provided by the participating laboratories, for the benefit of the patient.
The United Kingdom Accreditation Services (UKAS) has accredited Weqas for compliance with conformity assessment – General requirements for proficiency testing (ISO/CASCO 17043:2010). The Schedule of Accreditation is available on the UKAS website.
Samples are distributed to participants on a regular basis, with a window of between two and three weeks, depending on the programme, for analysis of samples and submission of results. All programmes provide a comprehensive statistical report following processing of a distribution’s returns. The report is designed to give a clear picture of a laboratory’s performance, to highlight any potential problem areas and to provide sufficient information to identify types of errors and assist in choosing corrective action.
Report Format Options
As of the 1st April we have moved to a paperless organisation and are encouraging all our participants to embrace our electronic on-line services and download via our secure interactive website, or opt to have your report emailed in PDF format straight to your inbox. For more information on our interactive service, please browse our Weqas Interactive section.
Annual subscription covers a period from April 1st to March 31st. Participants can join at any time throughout the year and will be invoiced on a pro rata basis.
On registration a distribution schedule is sent to all participants with information of which programme is to be distributed, a corresponding distribution code with send-out and return dates. To view our Distribution Schedule please visit our Participant Zone. Samples are dispatched within the UK by first class post, non-UK customers can choose between sample dispatch by Royal Mail International track & sign or Courier. Either can be paid on a per distribution basis or batched shipments covering several months distributions, shipped on dry ice. Programme costs will vary depending on the shipment method selected.
Individual Programme Detail
To view our full individual programmes on offer, search ‘EQA Programmes’ (next tab). Here you can download programme guides to learn more about our analyte ranges, stability studies and material usage.
Report Statistics and Interpretation
For information about report statistics and interpretation of reports, please download our guides; Interpretation of Lab EQA Reports and our Weqas Participant’s Manual.
Programme documentation and Method questionnaires for enrolment are also available via this link.
Please click on the links below for more information on individual programmes including:
- Analytes covered by the programme
- Stability studies
- Material descriptions and frequency of distribution
- Access to programme guides and method questionnaires
For more information on POCT EQA Programmes.
For information about report statistics and interpretation of reports, please download our Participant’s Manual.