Download WEQAS: what is it and what does it mean?.

WEQAS: what is it and what
does it mean?.
Celia Critchley
Point of Care Co-ordinator
Warrington and Halton Hospitals NHS
Foundation Trust
Objectives
• Overview of External Quality Assessment
and its relevance to health care
professionals and their patients
• Relationship between EQA and Quality
Standards in Healthcare
• Introduction to WEQAS
• Purpose of EQA
Objectives
• The Abbott I-Stat and Blood Gas EQA
• The WEQAS report – what does it mean
and what to look out for
• Examples
• Identifying problems and what to do about
them
External Quality Assessment
• EQA is defined as a system for
objectively checking a laboratory’s
performance using an external agency
or facility.
• Proficiency testing –an external provider
sends unknown samples for testing to a
set of laboratories, and the results of all
laboratories are analyzed, compared, and
reported to the laboratories.
• EQA helps to assure customers, such as
physicians, patients, and health
authorities, that the laboratory can
produce reliable results.
• Care Quality Commission
• NHSLA
• Clinical Pathology Accreditation (CPA) UK
WEQAS
• Wales External Quality Assessment
Scheme – WEQAS Quality Laboratory part
of the Cardiff and Vale University Health
Board
• Supplies Blood Gas and Co-oximetry
samples for Laboratory based and Point of
Care Testing instruments
Purpose of EQA
An evaluation of a participant’s measuring performance compared
with other laboratories using the same methods. Schemes can be
used to assess one or more of the following:
• The quality of the analytical performance of the participant’s
laboratory
• Intralaboratory variation
• Interlaboratory 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
• Systematic deviations for the individual laboratory from state-of-theart values or reference target values
The Abbott I-Stat and Blood Gas
EQA
• Currently around 160 I-Stat instruments
registered with WEQAS for Blood Gas
Scheme
• Monthly distribution of 3 samples per
instrument 2.5 ml sealed glass ampoules.
Tonometered protein based aqueous
material is used.
• Additional freshly tonometered bovine
blood sample distributed annually
The WEQAS Report - Analyte
Specific
The WEQAS Report – Analyte
Specific
The standard deviation shows how much a value varies from the
average or expected value (mean). A low standard deviation indicates
the data points are very close to the mean; a high standard deviation
indicates that the data points are spread out over a large range of
values.
Your report will show your reported result, your method mean and the
overall mean. WEQAS will calculate your results standard deviation from
the method mean (for pH (H+), pCO2 and pO2) and from this a standard
deviation index (SDI) score is calculated. The average SDI score is then
calculated for each analyte.
Also shown on the report is a graph of the previous distributions analyte SDI
score allowing an overview of any adverse trends
The WEQAS Report
The WEQAS Report
Other information included on the WEQAS
report:
• Bias plot (Bland Altman) for samples from
the current distribution and also from this
and previous distributions
• Precision and accuracy indicators
So…What should I be looking for??
Blood gas and pH on the I-Stat:
• Compare your results with method mean
(I-Stat)
• SDI for each sample analyte ideally <1; <2
is acceptable
• Review SDI graphs for previous
distributions to identify any adverse trends
• Managers performance summary gives an
easy-to-read indication of problems
Managers Performance Summary
Sheet
Managers Performance Summary
Sheet
Poor Performance Procedures
• Flag up as poor performer after 2 consecutive SDIs >2
on an individual analyte
• Contact from scheme organiser to notify participant of
poor performance and to offer assistance
• A response must be made and action taken within 3
months or a second letter is sent to the participant
• No response to second letter from WEQAS identifies the
participant as a persistent poor performer and the
appropriate National Quality Assessment Advisory Panel
(NQAAP) will be notified.
Help! I’m a poor performer!
Common causes of poor performance on
I-Stat EQA
• Incorrect WEQAS sample preparation by
operator
• Sample or cartridge temperature
• Incorrect storage conditions for cartridges
• Incorrect sampling technique
• Transcription errors
• Non-return of results!
What can I do?
• Ensure you are using the correct techniques for
EQA analysis as per WEQAS instructions
• Run IQC samples to check cartridge
performance
• Check cartridge storage temperatures / expiry
dates
• Request repeat samples from WEQAS
• Log any deviations from the procedure (e.g.
delay in analysis etc) at the time of running the
EQA
Where can I get advice?
•
•
•
•
Abbott Customer Helpline
WEQAS telephone enquiries
WEQAS.com
Your local laboratory (may have POCT
service)
Any Questions?