Assignment Tasks
TASK 1 – Staying in control
Word limit: maximum 3 pages (including control chart)
In this task you will be provided with a set of test data with which to construct a quality control chart. You
will then progressively apply the provided test data onto the chart and from which, using the Westgard Multi- rules outlined in lecture 6, you will be able to draw inferences concerning the state of control of the test
method. Cite your references using the APA Style.
The task consists of several steps:
1. Calculate the mean, standard deviation and ±1, ±2, and ±3 standard deviations for the set of test data. It is preferred that the calculated values are provided in a table;
2. Construct a control chart using the mean and the horizontal lines at ±1, ±2, and ±3 standard deviations from the mean. Progressively apply the sixty test results to this chart;
Hint: Microsoft Excel can be used.
3. Use the Westgard Multi-rules to assess the test data and whether:
a. the method appears to be in control;
b. the result should be treated as a “warning”; or
c. the results indicate a Westgard rule violation (a random or systematic failure of the method)
and the result should be rejected.
4. Identify and annotate the results in your chart at “warning” and “reject” points and indicate the applicable Westgard Multirule;
5. Provide a written commentary giving your interpretation of the state of control or otherwise of the method. Refer to point 3 for guidance on what to include.
Test data next page
Test Data
Sample 1 505 Sample 21 490 Sample 41 505
Sample 2 525 Sample 22 490 Sample 42 490
Sample 3 550 Sample 23 485 Sample 43 500
Sample 4 490 Sample 24 505 Sample 44 480
Sample 5 500 Sample 25 490 Sample 45 480
Sample 6 505 Sample 26 525 Sample 46 505
Sample 7 585 Sample 27 495 Sample 47 540
Sample 8 540 Sample 28 535 Sample 48 535
Sample 9 510 Sample 29 510 Sample 49 525
Sample 10 535 Sample 30 450 Sample 50 540
Sample 11 500 Sample 31 455 Sample 51 520
Sample 12 505 Sample 32 520 Sample 52 495
Sample 13 495 Sample 33 530 Sample 53 520
Sample 14 495 Sample 34 515 Sample 54 510
Sample 15 485 Sample 35 530 Sample 55 500
Sample 16 490 Sample 36 520 Sample 56 535
Sample 17 475 Sample 37 510 Sample 57 470
Sample 18 465 Sample 38 515 Sample 58 505
Sample 19 470 Sample 39 530 Sample 59 510
Sample 20 470 Sample 40 505 Sample 60 495
TASK 2 – The case of the complaining customer
Word limit: maximum 800 words
This scenario is directed at identifying a problem and working through a root cause analysis to solve a real life laboratory problem. Your task will be to identify a minimum of three (3) aspects of the laboratory’s management and operations that have led to the complaint, and identify the steps needed to correct the situation and ensure that it doesn’t happen again.
Read the case study involving an independent testing laboratory. Consider the information provided and:
1. Identify a minimum of three (3) aspects of the laboratory’s management and operations that appear to have contributed to the failure to meet the requirements of the Wise Water Testing laboratory’s contract with its customer, Larry Stevens;
2. Identify the specific clauses in ISO/IEC 17025 that relate to each of these aspects;
3. Identify what actions are needed to correct (i.e. immediate actions) the current situation;
4. Recommend actions (i.e. corrective actions) that could be taken to ensure that something similar does not happen again, either with Larry Stevens or any other customer.
Note: You have to present your response in a table format.
CASE STUDY SCENARIO Background
Wise Water Testing is a small multi-section laboratory, undertaking chemical and microbiological tests on waters. The laboratory is accredited to ISO/IEC 17025. The staff of the laboratory consist of a Laboratory Manager, two Section Leaders (Chemistry and Microbiology), and eleven testing personnel. There is a sample preparation area (Supervisor and one assistant) that comes under the responsibility of the Chemistry Section.
Complaint
The Laboratory Manager, Fred Mack, has just received an angry telephone call from Larry Stevens, the Chief
Engineer at one of the organisation’s very important clients, Safe Drinking Water Pty Ltd.
The customer told the Laboratory Manager that:
About 12 months ago, after a lot of negotiation, a contract was signed with the laboratory for the chemical and microbiological analysis of water samples of at an expected rate of 4 samples each week.
Since the samples are from the water treatment plant that provides drinking water to the towns of Bilabalah, Kottinga and Waniorah, the contract laid down strict protocols in relation to the tests being done in triplicate, the use of standard reference materials as controls, and the reporting of results.
Yesterday, Larry Stevens phoned the current Laboratory Manager to obtain further details of the results obtained on the latest samples, in particular the results for ammonia and Total Plate Count. These ammonia results were above the levels normally obtained for drinking water. The Total Plate Count was also high, with a result of 20 CFU/mL.
Because the results are on drinking water, Larry Stevens said that the residents of Bilabalah, Kottinga and Waniorah are now having to use bottled water at Safe Drinking Water’s expense. Safe Drinking Water will be seeking compensation from Wise Water Testing if these test results are found to be incorrect.
From the response given by the Laboratory Manager, it would appear that the work is not being done in accordance with the contractual conditions.
The Laboratory Manager agreed to investigate the matter personally.
Contract
After quite some difficulty, the Laboratory Manager located the original of the contract in the office of the organisation’s Legal Officer. The contract had been signed by the Legal Officer, and initialled by the previous Laboratory Manager, Christine Cameron. It required that:
a) each sample within each batch was to be analysed in triplicate;
b) each test batch was to include two standard reference materials as controls, these also being analysed in triplicate;
c) the standard reference materials were to be processed in exactly the same manner as the samples
with which they were associated;
d) test reports on each sample were to state the means of the triplicate results obtained on each sample and both reference materials, along with the range of results for each sample and standard;
e) Testing was to be done in accordance with the methods provided by Safe Drinking Water Pty Ltd.
Attached to the contract was a copy of a laboratory procedure, headed Supplementary Procedure 302 (Nutrients) and Supplementary Procedure 606 (Total Plate Count), prepared and authorised by Christine Cameron, which gave specific instructions on how these contract requirements were to be implemented.
LABORATORY MANAGER Fred Mack
The current Laboratory Manager is Fred Mack, who commenced in this position in October last year. Fred had come to the role as the Microbiology Section Leader. Fred claims that:
a) He was not aware of any specific contract with this customer relating to the processing of these samples, nor of any supplementary procedure.
b) He assumed that this customer’s tests would have been processed in accordance with the usual laboratory protocols – i.e. tests done in duplicate.
c) Normally test reports were prepared and signed by the Section Leaders. He thought that the form of reporting for this customer (mean and range of results) was unusual, but didn’t see any need to change the practice.
After some searching, Fred Mack found a copy of Supplementary Procedures 302 and 606 in the back of the procedures manual. It was not listed in the Index Page of the procedures manual. As the Document Controller for the organization, Fred was surprised to find this information buried in the procedures manual and wondered how he had missed this.
CHEMICAL SECTION LEADER Katy Graham
The Laboratory Manager, Fred Mack, questioned the Section Leader of the Chemical Group, Katy Graham, about the tests done for this customer.
a) Katy Graham disclaimed any knowledge of Supplementary Procedure 302 or any specific contract with this customer.
b) When records of the work done for this customer were examined, it was found that, up until December last year, each sample was analysed in triplicate and two standard reference materials with each batch, also analysed in triplicate. After December, samples were only analysed once and only one reference material was included in each batch of testing for the nutrients analysis.
c) From January onwards, there had been a significant backlog of work in the nutrients testing, even though an extra staff member had been recruited by the lab in December. Katy had provided training on how to perform the testing to Rose Hancock when she started in the lab.
Katy Graham claimed the change was the result of verbal instructions from the former Laboratory Manager, Christine Cameron. She couldn’t recall being given any reason for the change, and she didn’t think that she was ever given anything in writing to confirm the change.
LABORATORY TECHNICIAN Rose Hancock
Fred Mack and Katy Graham questioned the Laboratory Technician, about how this customer’s samples were processed.
a) Rose Hancock also disclaimed any knowledge of Supplementary Procedure 302 or any specific contract with this customer.
b) Rose explained that the processing of this customer’s samples followed the laboratory’s normal sample practices – when the samples arrived, their identification was checked against the customer’s order, they were allocated a laboratory test number, and then the samples were prepared and tested like other samples.
c) She mentioned in passing that, the section was always busy and this had been the case since January.
The instrument was breaking down regularly and this was what was causing the backlog.
d) Fred also mentioned at this point that the lab was constantly replacing the injection needle for the instrument and this was costing them a lot of money. Fred asked Rose if she knew how to change the needle on the instrument. Rose replied that she had not been shown how to do this in her training.
e) When records of the work done for this customer were examined, it was found that standard reference materials had been processed with each of the analytical batches from the first batch that arrived in March last year through to those that arrived in January, but from January onwards, there was no record of any standard reference materials having been processed. When asked about the change, Rose claimed that this had come as a verbal instruction from the Chemical Section Leader, Katy Graham.
CHEMICAL SECTION LEADER Katy Graham
The Laboratory Manager returned to the Chemical Laboratory Group to ask Katy Graham about the change in procedures.
a) Katy Graham confirmed that the original practice had been to use standard reference materials that had been through the same sample preparation processes as the samples themselves, but now they were just using controls drawn from stock solutions of the pre-digested standards.
b) Katy claimed that this change had been made on verbal instructions of the previous Laboratory Manager, Christine Cameron. She thought that Christine had simply told her that the special preparation of the standards was “just not needed any more”.
Katy Graham added that she remembered being quite relieved at this because the standard reference materials being used as controls were quite expensive to purchase and their high rate of consumption was creating big problems with the reagents budget, especially after the budget cuts announced last year by the Water Services Manager.
LABORATORY MANAGER’S MUSINGS
Katy Graham’s mention of last year’s budget cuts reminded the Laboratory Manager of the tense discussions that he had had with the Water Services Manager when Fred first started in the role.
When he first told Fred that non-salary operating costs had to be reduced by 10% for the new financial year, Fred had protested vigorously that this could not be done without compromising the laboratory’s quality of service.
Unable to persuade the Water Services Manager to rescind the budget cuts, Fred had issued a memo to all laboratory staff advising them of the decision, directing them to examine ways of reducing operating costs
within their areas of responsibility, and warning them that they would be held personally accountable for achievement of the required savings.
TASK 3 – Calibration and traceability of equipment
Word limit: maximum 1 page
This task requires you to apply the equipment calibration and traceability requirements of ISO/IEC 17025 for a case study laboratory situation, taking into account NATA’s recommended intervals for calibration of equipment – NATA General Accreditation Guidance: General equipment table. Cite your references using the
APA Style.
You are the Laboratory Manager of a well-established multi-section independent testing laboratory. The laboratory consists of four sections – General Chemistry, Environmental Chemistry, Sample Preparation and Administration.
The Board of Directors has decided that, in order to maintain its commercial viability, the laboratory must gain accreditation to ISO/IEC 17025. You’ve been advised that an experienced quality manager will shortly be recruited to coordinate the accreditation project but, in the meantime, you’ve been directed to at least get the equipment calibration back on track.
For historical reasons there has never been any central or coordinated calibration program, with each Section Head being responsible for the equipment within his/her own Section. You intend to use the accreditation project to break this impasse and introduce a centralised calibration system.
The Section Heads have given you lists of the key items of equipment in use in the laboratory, and these lists have highlighted significant differences in approaches amongst the Section Heads.
Your task is to draw up a calibration program that will ensure that all of the laboratory’s key items of equipment are maintained in calibration in accordance with ISO/IEC 17025 and NATA’s accreditation requirements.
Your program may be in the form of a table and should show for each generic type of equipment:
1. What external calibration (if any) is required, and at what intervals;
2. If internal calibration is acceptable, at what intervals and whether documented instructions are needed;
3. What additional internal checks are required, and at what intervals, and whether documented instructions are needed
4. How the requirements of ISO/IEC 17025 calibration status labelling is to be applied.
Equipment Lists
Sample Preparation Section
Balances
One top loading balance for rough weighing only – not calibrated.
One analytical balance checked occasionally by General Chemistry Lab
Sieves
Several sets of sieves used as received – not used for any quantitative work
Glassware
Drawn from General Chemistry Lab as needed
Thermometer
One working liquid-in-glass thermometer used for monitoring the oven – No records of any checks
Drying oven
Monitored with the working thermometer, not checked otherwise (used only for drying incoming samples (if required))
General Chemistry Section
Balances
Four analytical balances (various models) – serviced annually by NATA accredited balance calibration agency, with three-yearly calibration as required. All are due for recalibration in March next year.
One older top loading balance last calibrated in 2003, but no longer used.
Thermometers
Two liquid-in-glass reference thermometers – purchased with NATA calibration certificates (1999 and
2002 respectively).
Twelve liquid-in-glass working thermometers (various ranges) – checked every six months against a reference thermometer.
Ovens
Two controlled ovens – used mainly for determining moisture contents. Annual check of temperature uniformity and stability by external service agency (NATA accredited).
Glassware
Volumetric flasks subject to initial check to confirm accuracy; no records kept
Instruments
pH meter – usual checks with buffer solutions; no records kept
UV/Vis spectrometer – annual external service
Environmental Chemistry Section
Balances
Two analytical balances (purchased June 2004 and October 2006) – checked with standard reference masses before being placed into service; annual checks with reference masses thereafter.
Reference masses (stainless steel)
Purchased with National Measurement Laboratory calibration certificate (1.12.1998). No subsequent re-calibrations.
Thermometers
Five working thermometers (various ranges) – no records of checks or calibration.
Instruments
pH meter – Checked with buffer solutions; no records kept
Glassware
Volumetric flasks subject to initial check to confirm accuracy; no records kept
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