QUALITY CONTROL
Contents Page
Background ………………………………………… 2
Overview of Project …………………………….. 3
Stages of the Project ……………………………. 4
Final Report Guidelines ………………………… 8
Assessment of the Project …………………….. 11
Assay Procedure ………………………. 12 Report Sheets & Charts ………………………… 14
Appendix
Summary of Accuracy ………………… 18
Westgard Rules/Multirules ………… 19
EQA Brainstorming Topics ………….. 20 EQA Data Entry Template …………… 22
Albumin BCG Method Kit Insert …… 23
Quality and Analysis in Clinical Pathology Quality Control (QC) Project
LEARNING OUTCOMES:
Successful completion of this project requires you to provide evidence of the ability to:
• Apply and interpret quality control and external quality assessment statistics, rules and charts, and critically analyse performance data and apply complex reasoning to make recommendations for further practice in a real world clinical biochemistry context.
• Apply knowledge of Quality Assurance systems in Clinical Biochemistry.
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• applying Clinical Biochemistry knowledge and using digital technologies
and skills in scientific writing.
BACKGROUND:
Internal Quality Control (IQC) in a clinical biochemistry laboratory involves monitoring the quality of results, for each assay performed in the laboratory, at the time of the measurement. This involves the use of Quality
Control (QC) samples with known “Target” values which are run alongside patient samples under the same assay conditions. Certain Rules can then be applied to the QC sample results to verify or validate immediately that the assay procedure is “In Control” ie whether the QC result is “close enough” to the expected “Target” value.
The rules commonly used to determine the acceptability of the IQC results are known as the WESTGARD RULES and include aspects of both accuracy and precision. The set of rules commonly used in clinical laboratories can be found in the Appendix.
The results for patients’ test samples are not released if the QC results do not meet acceptable standards of accuracy and precision.
External Quality Assessment (EQA) involves comparison of one lab’s results for an EQA sample with those of other labs using the same method to measure the same analyte. In an EQA program the samples are provided by an external organisation (eg in Australia, RCPAQAP – Royal College of Pathologists Australasia Quality Assurance Program) and the concentration values of the samples are unknown to the laboratories performing the assay. The measured results are submitted to the external organisation and a comparative analysis is undertaken on the results submitted by all participating laboratories. The results of this analysis are forwarded to the laboratories and show how an individual lab is performing in comparison to the ‘peer’ group and how the particular method is performing overall. This external evaluation is retrospective.
NOTE: EQA samples do not impact release of patient test results – this is determined by the validation of the IQC samples for each assay on the day of assay.
OVERVIEW OF THE PROJECT :
Internal Quality Control (IQC)
You will measure the concentration of serum albumin in three samples – a Patient sample, and two QC Samples with known target values for albumin. You will trial the assay and recording of data in week 2 (training) and then repeat the analysis for 7 weeks (weeks 3-8 & 10) using the same IQC samples but a different patient sample each week; results and reports from these seven weeks will form part of your project final report. The IQC samples will be ‘normal’ and ‘abnormal’, that is one will have a concentration of albumin that falls within the reference range and one will have a concentration that falls outside the reference range for albumin for the given assay.
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You will be acting as a specific Laboratory (your ‘OWN’ Lab) and your weekly IQC results will be taken to represent your laboratory in its own Internal Quality Control (IQC) program. You will assess the IQC Samples’ results to determine whether they meet acceptable standards of accuracy and precision as determined by control rules, and whether the patient results of that run can be released to the requesting clinician.
External Quality Assessment (EQA)
In addition to attaining your IQC results, twice during the semester (weeks 7 and 10) you will assay two ‘EQA’ samples for serum albumin. The concentration of these extra samples will be unknown at the time of the assay.
You will record the results for your EQA samples, and the results of all students (acting as ‘labs’) will be collated as part of an EQA program modelled on ‘real world’ practice. As each result represents that of a specific lab, the collated results are those of up to 100 laboratories using the same method to analyse the same EQA serum albumin samples. For each of the EQA analyses, you will be provided a spreadsheet of collated lab results and a YOUDEN PLOT graphical representation of the data. You will then analyse the group results to assess a. The performance of your OWN LAB compared to the peer group and
b. The overall performance of the specific method used for analysing serum albumin.
The FOUR Stages of the QC Project
A. Individual weekly assays & results:
Perform the QC assay in each practical session individually using the procedure on pages 12-13 and record your absorbance values on the electronic report sheets. Then complete the following:
1. Calculate your IQC and patient concentration results, recording the fully worked calculations on the electronic IQC Report Sheet (see an example of the report format on page 14).
2. Calculate the Z-scores, recording the calculations and results on the IQC Report Sheet, and plot them on the Levey-Jennings Chart (see example page 17 but accessed and completed in the lab electronically). Z-Scores used in the pathology industry indicate the number of standard deviation (SD) units a result is from the expected Target value, and include + or – signs.
3. Assess the two IQC results (z-scores) and decide whether or not to release the patient result. Record your patient result ‘release decisions’ on the IQC Report Sheet. You will assess acceptability of the QC z-scores each week by applying two separate single Westgard control rules, the 1(2S) rule and, the 1(3S). To have acceptable accuracy using the 1(2S) rule the zscores must be within the inclusive range of -2 to +2. To have acceptable accuracy using the 1(3S) rule the z-scores must be within the inclusive range of -3 to +3.
(Note: in the final report, you will apply the Westgard Multirules to analyse IQC results)
4. For the EQA samples in Weeks 7 & 10, calculate the Albumin concentration, record your results on the electronic EQA REPORT (example format on page 15) and enter your concentration results through the
‘Google Form’ EQA data ‘portal’ provided in class.
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The Lab OWN IQC Report and the EQA Report forms must be fully completed electronically in class each week including all calculations. You will review the completed forms in class with a demonstrator or lab supervisor and save to your U drive unit/student folder once they have been signed. Reports that are not reviewed and signed in class on the day of assay will incur a mark penalty in the final QC report.
5. An Excel spreadsheet (similar in format to that on page 16) of the peer group EQA results from weeks 7 & 10, and including the Central Reference Value or Central Value (ie concentration) for each EQA sample and the Analytical Performance Specifications (APS), will be put on Blackboard.
Using this data, calculate the following values and enter them in the spreadsheet: a. The median concentration value using Excel
b. The range for the median ± APS
c. The range for the Central value ± APS
d. The range for the Central Value ± 3 APS
Include the detailed calculations specified on the spreadsheet on a separate page in your final report.
6. Partially completed Youden plots of the peer group EQA data will also be provided on Blackboard.
Using the calculated statistical data above, complete the plot incorporating: a.
Applicable axes’ numerical values
b. A cross (X) identifying your ‘OWN” lab result
Training weeks
Three practical learning experiences are provided as part of your IQC and EQA ‘training’:
1. In week 2 you will explore the assay and completing the required documentation. This prac is about ‘training’ in the assay and documentation system.
2. In week 3 you will ‘have a go’ at interpreting Levey Jennings charts using the Westgard Multirules (you will need to be able to do this to analyse your own data for your final report).
3. In Week 7 you will undertake the first EQA assay and explore the completion and analysis of Youden plots (again something you will need to do with your project data for the final report).
Requirements must be met for all sessions – no part marks will be awarded.
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B. EQA brainstorming workshops & discussion forum.
In Week 11 you will take part in a ‘brainstorming workshop’ followed by a discussion forum on key aspects of the EQA part of the QC project. These activities form part of the project assessment (see Note above)
When? Workshops are scheduled in Week 11 on Tuesday: 9-11 in P413A for prac class 1, 1-3 in P506 for prac 2, and 4-6 in S408 for prac 3. Friday discussion sessions will be held at the usual prac times in Q228.
What to bring? Please bring your laptops or tablets so you can access Blackboard and relevant QC project resources. There will also be larger COWs (computers on wheels) available for group use.
What will you do? Small groups of students (randomly chosen) from each laboratory time session will be allocated a topic or part of a topic relevant to the QC project. A list of topics is included in the appendix and topics will be randomly allocated to the groups by the end of week 10. Students are strongly encouraged to start thinking about all the topics as well as their allocated one as all topics are relevant to the project and final report.
In Week 11, the workshop session is allocated for students to get together to brainstorm their topic. A WIKI will be set up through Blackboard for each lab time session and, within it, a page for each group. Each group will post their thoughts, conclusions and questions about the topic on their group page. In the practical sessions of week 11 in
Q228, a group-nominated spokesperson will present these thoughts. The presentation of students’ thoughts and conclusions is not a formal presentation but a sharing of thoughts and ideas. This is a learning exercise, and feedback, comment and input from other students is strongly encouraged. Q228 is equipped with a computer to access resources eg wikis or spreadsheets for illustrative purposes. Each group of students will be focussing on their own topic, however to gain the most out of the discussion forum all students are encouraged to have
1) analysed the class data independently,
2) given considerable thought to the results and discussion section of their report and 3) come prepared with the completed EQA spreadsheets and Youden plots.
The rationale for these sessions is that students are able to learn well from explaining to and listening to other students and that this exercise will promote deeper understanding of EQA procedures and results analysis. The aim is to bring all students up to the same level of understanding about EQA and this exercise will be useful in finalising the EQA part of the QC Report. The wikis will be accessible to all students for their information. Please remember that the comments on the wikis will be added before the class discussions and there may be factual or data analysis errors or inconsistencies. The wiki comments should be used in conjunction with the outcomes of the discussion sessions to gain a more complete understanding of the EQA topics. Students may add comments to the wikis after the discussions.
You are required to produce a QC report based on your results (see page 8 for detailed guidelines).
A final project reflection is also included at the end of the report (see pg 7 for guidelines).
• The project report is due Sunday October by pm. The report is worth of the 45% allocated for your project.
• The report should be formatted using Arial font, size 11, 1.5 spacing and normal margins.
• Include a header on each page with your name and student number
• The project report is to be submitted Via Turnitin (the link will be in the QC project folder under Assessment on Blackboard) using the following file name format:
• Marks will be deducted for reports that do not conform to the format and submission guidelines.
NOTE:
NOTE:
Like the three training
Like the three training
weeks, the Week 11 activities are largely formative in nature however, along with the training weeks, participation and s
weeks, the Week 11 activities are largely formative in nature however, along with the training weeks, participation and s
atisfactory completion
atisfactory completion
of all requirements (including a group contribution to the wiki) is required for 5% of the final projec
of all requirements (including a group contribution to the wiki) is required for 5% of the final project mark. Nt mark. N
o part marks will be allocated
o part marks will be allocated
.
.
C. Final QC Report
C. Final QC Report


Process and requirements for submission
Process and requirements for submission
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• NOTE: Documents submitted will be assessed for plagiarism through Turnitin. Reports returning a score of 20% or greater as plagiarised may not be assessed. This limit applies to the body of the text only and we are able to easily distinguish instructions that are common to all eg on Youden plot sheets.
• Please note the policy for late submission as outlined in the unit outline.
D. Project Reflection
‘It is not sufficient simply to have an experience in order to learn. Without reflecting upon this experience it may quickly be forgotten, or its learning potential lost. It is from the feelings and thoughts emerging from this reflection that generalisations or concepts can be generated.
And it is generalisations that allow new situations to be tackled effectively.’ (Gibbs, G, 1988)
The QC project will provide you with an in depth learning experience about real world IQC and EQA practices. You are required to submit a reflection based on your learning experiences. To do this, first think about what you have learnt over the duration of the QC project, your participation and performance in the numerous learning experiences (not just practical sessions) and your thoughts and feelings as you progressed through the project. Then complete your reflection using the following guidelines based on Gibbs’ model of reflection (see below).
Reflection Guidelines
1. Feelings and Evaluation What were your reactions to and feelings about the different learning experiences in the QC project?
What was ‘good’ or ‘bad’ about the project?
2. Analysis What was the value for you of undertaking the project in terms of your development as a MLS? (This may incorporate knowledge, understanding,
experience and technical competence and confidence perspectives)
3. Conclusion and Action Plan Was there anything that would have improved your learning experience in the project or that you would do differently if you were to undertake this project (or similar) again?
Satisfactory completion of this reflection will require you to address all three guidelines above with evidence of having thought about the range of learning experiences within the project
It is very important to be genuine in your reflective writing – do not write what you think we may want to hear.
It is about your thoughts and feelings.
• This should be no more than 1 A4 pg
• Include this as the final page of your report formatted as the remainder of the report (see pg 6)
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Bibliography for Reflection Section
Gibbs, G. (1988) Learning by Doing: a guide to teaching and learning methods. Oxford: Oxford Brookes Further Education Unit
The Higher Education Academy (2013) Teaching reflective writing http://www.heacademy.ac.uk/resources/detail/newtoteaching/STEM-resources/teaching-reflective-writing
QC FINAL REPORT guidelines & requirements
COVER PAGE –
Include a report title, unit code and name, student name and number, and contents.
BACKGROUND/INTRODUCTION (no more than 1.5 page in total)
Accredited pathology laboratories operate within a regulatory framework that demands implementation, participation in and monitoring of IQC and EQA processes.
Explain
a) how each of IQC and EQA contribute to producing quality patient results (Note: this is not a description of IQC and EQA processes)
b) what ISO15189 and the NPAAC guidelines mandate pertaining to IQC and EQA with reference to the specific pertinent sections
Include a final one to two sentences on the overall rationale for this project in terms of your professional development as a medical laboratory scientist.
METHODS
Describe how each of the IQC and EQA parts of the QC project was organised, including what was analysed, how often and the assay used, the processes of recording/documentation, collation and analysis of results and the role of the individual student and the class in this model (1 page max). Do not reiterate the detailed content of the assay method or the report sheets.
RESULTS
Organise these into IQC and EQA sections
FOR IQC:
1. Include your seven completed IQC Report Sheets. Do not include the training assay report
2. Include your completed Levey-Jennings (LJ) Chart. Do not include the training chart.
3. Tabulate (in one table) the IQC results including:
a. concentration and z-score values for the normal and abnormal IQC samples for your completed runs
4-10, and the z-scores for the provided runs 1-3
b. the patient results (concentration values and whether the results are within, above or below the
Reference Range) for runs 4-10
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c. the release decisions based on each of the two single control rules in turn for runs 1-10
FOR EQA:
1. Include the two (weeks 7 and 10) completed EQA Reports
2. Include the two completed EQA peer group data spreadsheets and your calculations
3. Include the two (weeks 7 and 10) completed Youden plot data sheets
ANALYSIS OF RESULTS & DISCUSSION: Organise these into IQC and EQA sections
FOR IQC –
1. Tabulate the analysis of the results of your seven weekly runs using the Westgard Multirule approach to error detection. For each run, indicate which rules (if any) are triggered by that run’s IQC results, the type of error and whether the patient results would be released using the multirule approach.
Note: Results for 3 runs have already been included on your LJ chart. You will also include these results in your tabulated analysis and discussion. REMINDER! For a run to be deemed ‘in control’ and patients’ results released, both normal and abnormal control samples must be deemed ‘acceptable’
2. Drawing on your tabulated results, discuss
a. in terms of the Westgard Multirules and their statistical limits, why each of the weekly runs is ‘in control’ or ‘out of control’. (Tip: remember, as the number of runs increases, there will be more applicable rules in the Westgard Multirule approach)
b. the type of error (RE, SE or both) seen in the runs, and possible sources of that error in this project assay.
c. the implications for laboratory practice if runs are deemed “out of control” (this discussion is required even if all ‘your’ lab’s runs were in control).
3. The Westgard 1(2S) or 1(3S) (and sometimes other) ‘single’ rules are used by some laboratories instead of a Westgard multirule approach for error detection and determination of whether a run is in control or not.
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a. Discuss the advantages and disadvantages of each of the 1(2S) single rule and the 1(3S) single rule approaches and how the Westgard multirule approach overcomes any disadvantages of a single rule approach.
b. Drawing on your ‘own lab’ IQC results, comment on whether there were differences in the release decisions for patient results dependent on whether one of the single rules or the multirule approach was applied to your runs.
c. Discuss briefly which method of assessing the validity of your runs (1(2S) single rule, 1(3S) single rule or the multirules) you would recommend for ongoing measurement of serum albumin in your
‘OWN lab” and why.
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FOR EQA –
NOTE: for all analyses assume integrity of the EQA samples is not an issue.
1. Explain what ‘Central Values’ and Analytical Performance Specifications (APS) are and the significance of the centre square and peer review box on a Youden plot.
2. Comment on the performance of your individual lab with respect to the peer group for measuring serum albumin by the BCG method:
a. With reference to your completed Youden plots, comment on whether there is any apparent bias in your lab’s EQA results compared to the peer group and the nature of any identified bias. Explain your reasoning drawing on your lab results and the calculated numerical data for each of weeks 7 and 10,
b. There are a number of investigative actions that are recommended by the RCPAQAP if an EQA result is not in consensus with the peer group. The IQC of the same run can be looked at as part of this investigative action. Explain why – what can it tell you? Comment on the alignment of your IQC results with your EQA results. (This discussion is required irrespective of whether your own lab result was in consensus).
3. Comment on the overall performance of the BCG method for analysing serum albumin:
a. With reference to your completed Youden plots for weeks 7 and 10, comment on whether there is any bias in the BCG assay method for measuring serum albumin, and the nature of any bias. Explain your reasoning, drawing on the numerical data for both weeks.
a. From your understanding of this BCG method, comment on any identifiable reason(s) for any observed method bias
b. Does the performance of this BCG assay (ie any bias) as evidenced in the Youden plots present any issues that may be of clinical relevance or concern? Discuss.
4. Recommendation (no more than 0.5 page)
Drawing on your analysis of the performance of the BCG assay method, formulate a recommendation for your labs continued measurement of serum albumin. This is not a repeat of previously discussed results but a recommendation that draws on BCG method issues that you have identified through your analysis and that could or should be addressed to optimise measurement of serum albumin to ensure the best patient care. Your recommendation should re-state succinctly the method issues raised by the EQA results and then explain how a lab might address them
References – Vancouver format for in text referencing and the reference list
Remember – keep it organised, concise but complete, and relevant.
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ASSESSMENT OF THE PROJECT – Summary
The Project is worth 45% of your final unit mark.
Brainstorming Workshop and Discussion Sessions Week 11 and Training Weeks 2, 3, and 7 Weighting: 5% While largely formative in nature, participation and satisfactory completion (including associated documentation) in these activities is required to meet the learning outcomes of the unit and constitutes 5 of the 45% allocated to the project. To be eligible for the 5% students must participate in and satisfactorily complete all sessions – no part marks will be awarded.
QC Final Report
Weighting: 40%
Due: Sunday
Submission method: Turnitin via Blackboard site link in Assessment/QC project folder
Marking criteria – There will be a file on Blackboard in the QC project folder under Assessment Detailed report guidelines can be found on pages 7-10 of this document.
NOTE: Documents will be assessed for plagiarism through Turnitin.
Late Submission
In line with current policy, late submissions without an approved extension will not be marked and will receive a grade of 1 or 0%.
QC Assay– Serum Albumin by the Bromocresol (BCG) Method.
NOTE: The same assay is performed for both IQC and EQA analyses.
1. To 5 labelled tubes (microfuge tubes, 2 mL) add 900 μL Bromocresol Green (BCG) reagent
(labelled ‘Albumin BCG reagent’). Pre-Incubate tubes at 37oC in the heat block for 10 minutes.
In Weeks 7 and 10 only, prepare two extra tubes containing 900 μL BCG Reagent.
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2. To the 5 tubes, add 9.0 μL of one of the following (follow table below)
• Distilled water
• Standard (with a known, accurate concentration of albumin)
• IQC Normal serum sample (which has a known “Target Value” albumin concentration)
• IQC Abnormal serum sample (which has a known “Target Value” albumin concentration)
• Patient serum sample (with an unknown concentration of albumin)
In Weeks 7 and 10, to tubes 6 & 7 add 9.0 μL of one the following (follow table):
• EQA Albumin Sample (A) (with an unknown Target value) EQA Albumin Sample (B) (with an unknown Target value)
Table 1. Serum Albumin QC Assay – BCG method; Contents of Tubes
Tube 1
Reagent
Blank
Tube 2 Standard
Tube 3
IQC
Normal
Tube 4
IQC
Abnormal
Tube 5
Patient sample Tube 6 (Wks 7, 10) EQA A Tube 7 (Wks 7 10) EQA B
BCG (0.26 mmol/L)
900 μL
900 μL
900 μL
900 μL
900 μL 900 μL 900 μL
Distilled water
9.0 μL
Standard
9.0 μL
IQC
9.0 μL
9.0 μL
EQA (A) (Wks 7, 10 only) 9.0μL 10 only) 9.0 μL EQA (B)
(Wks 7,
Patient Sample
9.0 μL
Total Volume
909 μL
909 μL
909 μL
909 μL
909 μL 909 μL 909 μL
Concentration of Albumin
Zero
Known
“Known”
Target
“Known”
Target
Unknown Unknown Unknown
3. Mix each tube immediately after addition using a vortex and incubate each tube for exactly 90 seconds at 37oC. The reagent blank does not need a timed incubation (no reaction will occur).
,
,
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4. Read the absorbance of tubes 2-5 (2-7 in weeks 7 and 10) at 630 nm vs the Reagent Blank (ie. Set Ref or zero absorbance with Tube 1) immediately after the 90s incubation period and record on report sheet
5. Calculate the two IQC and Patient concentration results using Beers’ Law as set out on the report sheet and record the calculations and results on the IQC report sheet.
6. In Weeks 7 & 10 also calculate the two EQA sample concentration results using Beers’ Law and record results on the EQA report Sheet and also on the Google Docs data portal entry form.
7. Calculate the z-scores for the two IQC samples, record the calculations and results on the report sheet and determine the validity (acceptability) of the patient result as specified on the report sheet.
8. Complete the report sheet(s) and save it electronically for demonstrator review and supervisor’s signature.
9. Record your z-score results on the electronic LJ chart.
REMINDER: No report sheets will be reviewed after the day of the assay and reports that have not been reviewed will incur a mark penalty in the final report.
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EQA OWN LAB Report Data Sheet – Serum Albumin by BCG Method
Given value: Standard albumin concentration: 41.9 g/L
Calculation formula: Assuming that Beer’s Law is obeyed (NB. Only 1 standard is used):
[QC] = A QC x [Std]
A Std
EQA Report 1- Week 7 Date:……………………….Instrument: ………………………………………………………………………………….. ‘Absorbance’ standard = ___________ ‘Absorbance’ EQA Sample (A) = ___________ ‘Absorbance’ EQA Sample (B) = ___________ Calculations for EQA samples Serum Albumin EQA Samples: Week 7 Calculated EQA Sample (A) concentration = ……………. g/L Calculated EQA Sample (B) concentration = ……………. g/L Concentration Analyst’s name: …………………………………………………. (Uppercase letters): Supervisor’s Signature:
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…………………………………………….
All values should be in g/L, therefore only the number eg 40.0 is included in the Table to keep it uncluttered.
EQA Serum Albumin Sample:
Wk 7 (A)
Wk 7 (B)
Date of assay:-
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Peer Group Lab EQA Results Include a key to:
• Identify OWN lab EQA results
• Identify values outside the
Central Value APS range
**Central value ± APS
Show range of values
NB: Example only: 36.0 to 41.0 g/L
**Central value + 3APS
**Central value – 3APS values outside or equal to Central
Value 3APS will appear on the outside edges of the Youden Plot
Median of data set
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**Median ± APS
Show range of values
**YOU ARE REQUIRED TO INCLUDE CLEARLY EXPLAINED, FULL CALCULATIONS TO SHOW HOW
YOU DERIVED THESE VALUES FOR EACH SAMPLE – PLEASE INCLUDE A SEPARATE CALCULATIONS SHEET.
Albumin EQA Samples Central Values:
Wk 7 EQA (A): g/L
Wk 7 EQA (B): g/L
Albumin assay
Analytical Performance
Specifications (APS):
+/- 2.0 up to 33.0 g/L
+/- 6% >33.0 g/L
Albumin Reference Interval:
33 to 48 g/L
Clinical Decision Points:
20 g/L
33 g/L 52 g/L
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QC SUMMARY PAGE – Accuracy
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APPENDIX
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Accuracy relates to attaining a result which is close to the “True” value. In IQC, Z-scores allow assessment of (In)Accuracy and in EQA, Analytical Performance Specifications (APS) determine acceptable limits of accuracy.
1. IQC assesses accuracy of the run using z-scores for the IQC samples and then application of Westgard rules (either single rules or using the multirule approach). (Precision over time can also be assessed using the Westgard multirule procedure).
2. EQA assesses:-
a. Accuracy of a Lab’s performance compared to the peer group:-
i. Comparison of own lab values for two levels of EQA samples to the
‘median ± APS range’ for the peer group.
ii. A Youden plot shows this graphically
b. Accuracy of the method being used by the peer group.
i. ‘Median value for peer group ± APS’ range of values is compared to Central Value ±
APS’ range of values. ii. A Youden plot shows this graphically
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2. WESTGARD RULES in common use APPENDIX
• Rules
– 1(2S): Control exceeds 2SD from the target value (Warning)
– 1(3S): Control exceeds 3SD from the target value (Reject RE)
– 2(2S): 2 consecutive controls exceed 2SD from the target value in the same direction (Reject RE or SE)
– R(4S): 2 controls differ by >4SD in the same run (Reject RE)
– 4(1S): 4 consecutive controls > 1SD from the target value in the same direction (Reject SE)
– 10(X): 10 consecutive controls on the same same side of the target value (Reject SE)
• RE = random error (imprecision)
• SE = systematic error (inaccuracy)
3. External Quality Assurance (EQA) Topics for Brainstorming & Discussion (Week 11 tutorial session)
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APPENDIX LSB425 Quality and Analysis in Clinical Pathology (Q&A)
QUALITY CONTROL (QC) PROJECT
1. EQA Overview – How is EQA conducted in a ‘Real World’ Medical Laboratory?
• What is EQA and how does it contribute to ensuring quality patient results?
• Who runs EQA programs in Australia?
• How is the program conducted – ie what does the lab do & what does the external organisation do?
• What are Central Values and how are they derived?
2. EQA Project Overview
• Rationale for this part of the QC project – why are you doing it?.
• How is it organised (eg how often, # levels control, values of controls etc)?
• In this model – what do individual results represent? Class results? • Data record, collation, analysis
etc
3. Youden Plots – an example EQA report might assist here What are they?
• How are they constructed? o What do x and y axes represent?
o What values go on the axes?
• What information can they provide about o A lab’s performance of a method? o The method itself?
4. The Centre Square and Peer Review Box (PRB) – an example EQA report might assist here
• What does the centre square represent in terms of method?
• How is the centre square on a Youden plot defined numerically?
• What does the Peer Review Box represent in terms of method and why is it included on a Youden plot?
• How is the PRB defined numerically?
5. Analytical Performance Specifications
• What are these limits and what is their importance clinically?
• What is the format of APS?
• How are they used to assess method performance? o What do you look at and compare – visually and numerically?
• How are they used in assessing lab performance? o What do you look at and compare – visually and numerically?
An example EQA report might assist here.
6. Lab performance not in Consensus with the Peer Group What investigative actions should be taken – troubleshooting?
• How can IQC results inform the troubleshooting?
• Are there implications for lab practice? Are there implications for Patient results?
• What if the lab results are within the target value ± APS but not in consensus with the group ie not within the group median ± APS? Which is more important – why?
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7. Bias in the BCG Method
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Is there? What type of bias if any?
How do you tell visually from the Youden plot? Numerically?
Is it a problem for analysis of Albumin using this BCG method?
o Consider clinical decision points (what are they?) – does any bias observed impact on them?
o Potential end user implications (doctor, patient)
If there is a problem with the method, what could be done?
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Example of ‘Google Forms’ Data Portal for EQA Results
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APPENDIX
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