LGC AXIO Proficiency Testing 2023 - Water & Environmental S…

Proficiency testing schemes and samples provided by LGC AXIO Proficiency Testing for the water and environmental sector throughout 2023.

Water & Environmental Proficiency Testing Schemes

2023 Catalogue


ISO/IEC 17043


LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue


LGC AXIO Proficiency Testing operates a wide range of water & environmental schemes and programmes, so whatever your quality needs, AXIO will deliver the confidence in your results that you are looking for.



Your local AXIO office


Driving Quality Together




The PT process


Water & Environmental PT schemes by AXIO


What's new for 2023?


Water chemistry (AQUACHECK)


Air and stack emissions (AIR PT)


Water microbiology (QWAS)


Contaminated land (CONTEST)


Cryptosporidium (CRYPTS)


Hygiene surface monitoring (HYGIENE)


Additional resources


Frequently Asked Questions


Dr. Ehrenstorfer




Order PT

This water & environmental brochure is an interactive catalogue. This means that you can quickly search for analytes of interest by clicking the magnifying glass icon in the top right hand corner. You can also click on links to go to forms, watch videos, or go directly to relevant materials.



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

LGC AXIO Proficiency Testing provides schemes with localised support across a truly global network.

2,700+ Annual proficiency tests

13,000+ Laboratories served worldwide

160+ Serving laboratories in over 160 countries worldwide
















For further information please contact one of our local sales offices.

China T: +86 400 9216156 E: pt.china@lgcgroup.com France T: +33 (0)3 88 04 82 82 E: axiopt.fr@lgcgroup.com Germany T: +49 (0)281 9887 0 E: axiopt.de@lgcgroup.com India T: +91 98491 87576 E: axiopt.in@lgcgroup.com 1 2 3 4

Italy T: +39 02 22476412 E: axiopt.it@lgcgroup.com Middle East T: +49 (0)281 9887 0 E: axiopt.de@lgcgroup.com Nordic countries T: +49 (0)281 9887 0 E: axiopt.de@lgcgroup.com Poland T: +48 22 751 31 40 E: axiopt.pl@lgcgroup.com 5 6 7 8

Russia T: +48 22 751 31 40 E: axiopt.pl@lgcgroup.com South Africa T: +27 (0)11 466 4321 E: axiopt.za@lgcgroup.com South America T: +44 (0)161 762 2500 axiopt@lgcgroup.com Spain T: +34 (0)93 308 4181 E: axiopt.es@lgcgroup.com 12 9 10 11

United Kingdom T: +44 (0)161 762 2500 E: axiopt@lgcgroup.com USA + Canada T: +1 231 668 9700 E: axiopt.us@lgcgroup.com If your country is not listed 13 14 15

above please contact: T: +44 (0)161 762 2500 axiopt@lgcgroup.com



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

Great results are born out of confidence and by working with LGC AXIO Proficiency Testing you can ensure that your decision making is informed, accurate and reliable.

Driving Quality Together.

We design our schemes to meet your laboratory’s future needs. It’s what helps you consistently deliver a quality product, meet sector specific standards or achieve accreditation to ISO/IEC 17025 or ISO 15189.

Fulfill accreditation requirements

Demonstrate competency to customers & regulatory bodies

Compare results with peers across the world

Manage risk through early warning of potential problems

Verify methods & instrumentation

Educate & train staff


Proficiency Testing (PT) is a requirement for accreditation to ISO/IEC 17025 and ISO 15189. AXIO operates PT schemes across the food, beverage, environmental, clinical, pharmaceutical, consumer safety, forensic and petroleum sectors – your laboratory will get the support it needs in demonstrating the effectiveness of your quality system. If you are managing multiple laboratories and are looking for consistency in results, AXIO offers fully managed solutions for large groups. Multi- laboratory, multi-method and multi-analyst reporting are all covered by our exclusive web based PORTAL platform. Using an accredited PT provider gives you assurance in the quality and reliability of the service. LGC is a UKAS (United Kingdom Accreditation Service) accredited proficiency testing provider (ISO/IEC 17043) No. 0001. In addition we are certified to ISO 9001.



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue


PORTAL sits at the core of the LGC AXIO Proficiency Testing process. PORTAL is your gateway to improving laboratory performance: an online hub for results submissions, report downloads, data export and trend analysis — anytime, anywhere.

NEW: PORTAL now available to users in English, French, German, Mandarin, Polish and Spanish!

Full control of all of your LGC AXIO Proficiency Testing data 24 hours a day. portal.lgcstandards.com



Laboratory proficiency relies on trusted expertise and an efficient reporting process, which is why we've designed our comprehensive service around your laboratory's needs. THE AXIO PT PROC ES S

Download the PORTAL user guide to learn more on how to utilise PORTAL to drive quality in your laboratory.




LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

Water & environmental proficiency testing schemes LGC AXIO Proficiency Testing operates schemes for the food and feed sector. Whatever your quality and testing needs, AXIO will have the scheme and sample options that will deliver the confidence in your results that you are looking for. AQUACHECK Water Chemistry CRYPTS Cryptosporidium

QWAS Water Microbiology

CON TEST Contaminated Land

AIR PT Air & Stack Emissions HYGIENE Hygiene Surface Monitoring ________________________________________________________________


What's new for 2023? As your partner in proficiency LGC AXIO Proficiency Testing is continually evolving the range of samples we offer to our global laboratory network. The following is what is new for 2023 for the water & environmental sector. Sample PT-AQ-1HP (Major Inorganic Components in hard, potable (treated) water). This will be available in round AQ641 (February 2023) Sample PT-AQ-1SP (Major Inorganic Components in soft, potable (treated) water). This will be available in round AQ641 (February 2023) Sample PT-AQ-2HP

(Nutrients and Others in hard, potable (treated) water). This will be available in round AQ641 (February 2023) Sample PT-AQ-2SP

(Nutrients and Others in soft, potable (treated) water). This will be available in round AQ641 (February 2023) Sample PT-AQ-67 (Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in groundwater). This will be available in round AQ640 (January 2023) Sample PT-WT-431 (Somatic coliphages in water). This will be available in round WT330 (October 2023) Sample PT-HY-12 (Enumeration of Enterobacteriaceae using contact plates). This will be available in round HY327 (July 2023) Sample PT-HY-13

(Detection of Salmonella in ready to test sponge). This will be available in round HY327 (July 2023) Sample PT-HY-14 (Detection of Listeria in ready to test sponge). This will be available in round HY331 (November 2023)

View new proficiency testing samples in all sectors here.



Application form

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AQUACHECK Water Chemistry

Water is vital in sustaining all natural systems, and each source requires regular analysis to determine the safety and suitability of use. Potable water must be good in quality and quantity and free from harmful chemicals and microorganisms. Discharged water from local wastewater treatment plants and industries must comply with environmental guidelines. Process waters must be kept clean to ensure product quality. As water sources can change, regular testing is advised. AXIO Proficiency Testing offers the industry-leading AQUACHECK scheme that has been in continuous operation since 1985. Test materials are provided for the analysis of major inorganic/organics, metals, phenols, organochlorine pesticides, and many others. Participation in the AXIO AQUACHECK scheme allows laboratories to identify problems before they affect the quality and safety of waters. Participants will be able to demonstrate independently that they are producing accurate and meaningful results to laboratory management and customers.

Test Material* Analyte* Clean water (Organics)

Acid herbicides, Acrylamide, BTEX, Chlorinated solvents, Chlorophyll a, Fungicides, Geosmin and MIB, Haloform solvents, OC and OP pesticides, PAHs, PCBs, PFOA, PFOS, Formaldehyde, Phenols, Taste and odour, Triazines and Urea herbicides, Neonicotinoids, UV absorbing organics constituents.

Clean water (Radiochemistry) Ground water Qualitative water (Organics)

Aqueous tritium, Gross alpha, Gross beta.

Metals, Toxic metals, PFAs.

Organics by purge, trap and/or headspace GCMS, Qualitative determination of unknown contaminant. BOD, Chromium (VI), COD, DOC, MBAS, Metals, Non-ionic surfactants, Suspended solids, Toxic metals, Turbidity, Microcystins.

Clean water (Inorganics) Poorly buffered water


Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Molybdenum, Nickel, Vanadium, Zinc, Selenium, Total boron, Water extractable boron, Fluoride, Total nitrogen, Total phosphorus, Total potassium, Cobalt, Iron, Manganese, Total solids, Loss on ignition, pH, Extractable phosphorus, Extraction of potassium, Extraction of magnesium, Extraction of sodium, Organic carbon content, Conductivity, Carbonate content.


Chlorine (free, total), Inorganic disinfection by-products.

Clean water Hard and soft surface water Hard and soft potable water (Inorganics) Ecotoxicology High salinity potable water

Colour, Conductivity, Major inorganic components, Nutrients and others, pH, TDS.

Ecotoxicology tests.

Conductivity, Major ions, pH, TOC, TDS.

Acid herbicides, AOX, BTEX, Chlorinated solvents, Haloforms, OC and OP pesticides, Phenols, PCBs, PAHs, Triazines and Urea herbicides. Mineral oil, Oil and grease. BOD, Chromium (VI), COD, DOC, Metals, MBAS, Non-ionic surfactants, Non specific analytes, Nutrients and other analytes, Settleable solids, Suspended solids, Toxic metals, Turbidity. Ammonia, Cyanide, Major wastewater analytes, Metals, Nitrogen, Phenol (total), Phosphate, Sulfate, Sulfide (total). Arsenic, Cadmium, Chromium, Cobalt, Copper, Fluoride, Iron, Lead, Manganese, Mercury, Molybdenum, Nickel, Selenium, Total boron, Total nitrogen, Total phosphorus, Total potassium, Vanadium, Zinc.


Effluents & wastewater Effluents & wastewater (Industrial)


* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/ scheme description.


Application form

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AIR PT Air & Stack Emissions

We take air for granted: it is ubiquitous, essential, and life-giving. However, it is easily polluted by our activity and so requires regular monitoring to assess exposures and the effectiveness of containment or ventilation. Many everyday activities create air pollutants with known or suspected harmful effects on human health and the environment. Such pollution can cause both short and long-term effects on human, plant, and animal life. Our Air Stacks & Emissions Scheme (AIR PT) is a partnership between AXIO Proficiency Testing and the UK Health and Safety Executive. The scheme is operated by AXIO and supported by the technical testing and monitoring expertise at HSE. AIR PT combines our scientific and production expertise in different areas, providing an integrated solution for all laboratories undertaking analysis of samples from various fields of air monitoring. Participation in the AIR PT scheme supports a laboratory’s quality system in the monitoring and measurement of air quality in a wide range of contexts.

Test Material*


Workplace air (filters)

Aldehydes, Chromium (VI), Metals, Respirable grade quartz by FTIR and XRD.

Workplace air (diffusion tubes)

VOCs (charcoal sorbent and thermal desorption).


Workplace air (dust) Ambient air (filters)

Anions, Metals.

Ambient air (diffusion tubes) Indoor/chamber air (diffusion tubes) Stack emissions (impinger solutions) Stack emissions (rinsing solution) Gravimetric filters (workplace air, ambient air, stack emissions)

Nitrogen dioxide (as nitrite), VOCs (thermal desorption).

Qualitative and quantitative VOCs (charcoal sorbent and thermal desorption).

Ammonia, Hydrogen chloride, Hydrogen fluoride, Mercury, Nitrogen oxides as (NO2), Sulphur dioxide, Metals, Volume of solution.

Dust (total solids).

Dust by gravimetry (mass of solids), Fly ash, Metals.

* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/ scheme description. LGC is the accredited provider of the PT scheme.



Application form

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Q W AS Water Microbiology

Microorganisms occur in water naturally, the majority are relatively harmless; however, contamination of water from faecal sources can lead to large outbreaks of disease. In many countries, water microbiology is the subject of legislation. Regulations specify how often water sources are sampled, how sampling is done, how the analysis will be performed, for which microorganisms to test, and the acceptable limits for the target microorganisms. The AXIO Proficiency Testing Quality in Water Analysis Scheme (QWAS) has been specifically developed for the microbiological analysis of waters and effluent sludge. Participation in QWAS can provide laboratories with confidence that the results of this analysis and the equipment used to produce those results are meaningful and accurate which, in turn, helps to ensure water safety.

Test Material* Analyte* Bathing,

Total aerobic count, Coagulase-positive staphylococci, Staphylococcus species, Sulphite-reducing Clostridia, Clostridium perfingens

recreational & surface water Bathing, surface & wastewater

Enterococci (faecal streptococci), Escherichia coli, Faecal coliforms, Total coliforms, Salmonella species.

Effluent sludge

Escherichia coli, Salmonella species.

Dialysis water

Total Aerobic Count.

Environmental water

Legionella pneumophila by culture, Legionella pneumophila by PCR. Legionella species by culture, Legionella species by PCR. Clostridium perfringens, Coliforms, Enterococci (faecal streptococci), Escherichia coli, Pseudomonas aeruginosa, Sulphite-reducing Clostridia, Sulphite-reducing Clostridia spores ONLY, Total aerobic count at 22°C and 37°C, Legionella species (low levels) Yeast and mould. Identification of (non-pathogenic) organism to correct family, genus or species level, Somatic coliphages. Pseudomonas aeruginosa, Pseudomonas species, Total aerobic count, Yeast, Mould, Yeast and mould (total).

Potable water

Process water

Enterococci (faecal streptococci), Escherichia coli, Faecal coliforms, Total coliforms.

Sea water

Lyophilised material

Unknown microorganism.

Waste water


Paper exercise (image)

Colony count and calculation of number of microorganisms.

* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/scheme description.


Application form

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CRYPTS Cryptosporidium

Cryptosporidium is a parasite found in water that can cause illness in humans, as demonstrated in many recent cryptosporidium outbreaks that have threatened public health. Potable or recreational waters should be treated to remove cryptosporidium; samples are therefore regularly tested through the water industry to ensure that treatment has worked and water supplies are free from cryptosporidium. Guidelines exist, such as those from the WHO and the EPA, to ensure cryptosporidium doesn't contaminate human water supplies. The AXIO Proficiency Testing CRYPTS scheme enables participants to show the validity of their methods and results, with samples including slides, suspensions, and filters with Cryptosporidium oocysts.

Test Material* Analyte * Dynal slides

Enumeration of Cryptosporidium oocysts.

Genera slides

Enumeration of Cryptosporidium oocysts.

Suspensions Enumeration of Cryptosporidium oocysts. Filta-Max silters Enumeration of Cryptosporidium oocysts. Xpress ilters Enumeration of Cryptosporidium oocysts.

* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/scheme description.

15 www.lgcstandards.com/AXIO

Application form

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CONTEST Contaminated land

Land contamination can pose both environmental and human health risks. The main causes of contamination are the direct discharge of industrial wastes, domestic pollution, over-use of pesticides, oil and fuel dumping, leaching of wastes from landfills, and leaking underground storage tanks that corrode over time, releasing toxic substances into previously clean soils. Participation in a proficiency testing scheme for soil, such as the AXIO Proficiency Testing CONTEST Scheme, is a requirement of the UK Environment Agency’s Monitoring Certification Scheme (MCERTS) ‘Performance Standard for Laboratories Undertaking Chemical Testing of Soil’. CONTEST covers a comprehensive range of analytes in soils, soil extracts, and standards solutions for the analysis of metals, inorganic contaminants, organics, soil leachates, and solid waste.

Test Material* Analyte* Soil, acid extract of soil, standard solution

Chromium (VI), Metals, Toxic metals.

Ammonia, Cyanide (complex, free, total), Dry matter, Easily liberated sulfide, Fluoride (total), Loss on ignition, pH, Sulfate (total), Sulfur (total), Thiocyanate, Water soluble (boron, chloride, fluoride, sulfate), Distillable phenolic substances, Elemental sulfur, Phenols, PAHs, PCBs, TOC, TPHs, VOCs, Soil texture.

Soil &/or standard solution

Soil, standard solution

TPH, VOCs, OC pesticides, OP Pesticides.

COD, Conductivity, Cyanide (complex, free), Major ions, Metals, pH, PI,Thiocyanide, TOC/DOC, Toxic metals.

Soil leachate

Soil waste & leachate (waste acceptance criteria)

DOC, Dry matter content ratio, Major ions, Metals, PI, TDS, Toxic metals.

Standard solution

Qualitative test of SVOCs.

Loss on ignition (FINES).

Trommel fines

Incinerator bottom

Ash, Toxic metals, pH, Alkali reserve.

* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/scheme description.


Application form

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HYGIENE Hygiene Surface Monitoring

Regular hygiene monitoring of environmental surfaces and equipment in manufacturing and healthcare is a key part of any quality system. Ensuring control of microbial contamination can directly affect the quality of both product and patient care. In food and beverage industries, it can help avoid food spoilage and food poisoning, both of which can damage brand value and profits. In pharmaceutical manufacturing, parenteral medicines and the environment they are produced in need to be free from harmful microbial strains. In healthcare, regular environmental monitoring can demonstrate cleaning and disinfection has been carried out correctly, helping to reduce the potential spread of infection. Participation in AXIOs HYGIENE scheme can help to demonstrate that environmental monitoring is effective and under control. Regular monitoring allows information to be collected to review and assess hygiene quality and ensure legislative standards are being met. It also helps to determine the effectiveness of control systems designed to prevent microbial contamination.

Test Material*


Enumeration of Enterobacteriaceae, E. coli, Total aerobic mesophilic count, Yeasts and/or Moulds. Detection of Listeria species, Listeria monocytogenes, Salmonella species. Enumeration of Staphylococcus aureus, Yeast, Mould, Total aerobic mesophilic count, Enterobacteriaceae.

Surface testing by swabbing

Surface testing by Contact plates Surface testing by dip-slides Surface testing by ATP monitoring Surface testing (Swab rinsate or dry swab)

Enumeration of Coliforms, Total viable count.

ATP levels.

Detection of SARS-CoV-2.

Enumeration of Yeast; Mould; Yeast and Mould; Enterobacteriaceae; Coliforms; Escherichia coli;Total aerobic mesophilic count. Detection of Listeria species; Listeria monocytogenes; Salmonella species; E. coli O157 (non-toxigenic strain).

Swab rinsate

Air filter

Total viable count; Yeasts and/or Moulds.

Salmonella sp; Listeria sp; Listeria monocytogenes.

Ready to test sponge

* The full range and availability of test materials and analytes is determined on an annual basis and may be added or removed. For accredited and non-accredited status please see current application form/scheme description.

Can't find a specific test? Request a new sample here.

17 www.lgcstandards.com/AXIO

Additional resources

White papers

Industry webinars

Environmental Evolution: How analytical science is adapting to increasing concerns and legislation of PFAS & Neonicotinoids


Confidence with Food Contact: How laboratories maintain pace with Food Contact Material testing


COVID 19: SARS-CoV-2 testing beyond the clinical space



Supporting the fight against pesticide and PFAS pollution, interview with two LGC experts


Water wonder woman, Rita Sharma, tells all on AQUACHECK


Beating the bioburden: how clinical, pharma and food labs can achieve continuous contamination air control


How sustainable quality processes can secure a sustainable future



Frequently Asked Questions



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

About Proficiency Testing

What is proficiency testing? Proficiency Testing (PT) provides a regular independent assessment of the the technical performance of a laboratory to assure the validity of measurements and tests, which should form part of an overall quality strategy. PT is often referred to as external quality assessment (EQA), especially in the medical/ clinical arena. The practice of testing unknown test materials from an outside source provides an additional, independent, means to assure the quality of laboratory test results. One of the most common designs for a PT scheme is for the provider to designate specific dates throughout the year when it will send test materials to all participants at the same time. The test materials, whose expected values are unknown to the subscribers, are analysed by the laboratory staff who return their results to the proficiency testing provider. The results are reviewed (using statistical techniques described in ISO 13528) to determine acceptable performance levels, and an evaluation is issued to each participant. The evaluation and accompanying statistical data not only capture the laboratory’s current performance, but over time allow the quality team to analyse trends and improve the laboratory’s long term performance. Proficiency testing is a key element in the laboratory accreditation process, alongside reference materials, enabling laboratories to monitor the quality of their analytical results as stipulated in ISO/IEC 17025 and ISO 15189.

Why enrol in a proficiency testing scheme? • Compare your laboratory’s results to those of others performing the same test or measurement. • Demonstrate and identify performance trends. • Monitor test performance across all of your organisation’s laboratories. • Complement internal check sample programs. • Demonstrate competency to customers, accreditation bodies and other regulatory bodies. • Fulfil accreditation requirements. • Verify methods and instrumentation. • Manage risk through early warning of potential problems. • Educate and train staff. • Check the reasonableness of the laboratory’s estimated measurement uncertainty.


About AXIO Proficiency Testing

Which international standards are relevant to LGC AXIO Proficiency Testing schemes? In terms of stipulating the use of proficiency testing, the main standards are ISO/IEC 17025 - General requirements for the competence of testing and calibration laboratories; and the clinical standard ISO 15189 - Medical laboratories – requirements for quality and competence. All our PT schemes are operated in accordance with the international standard ISO/ IEC 17043. The statistical analysis undertaken is in accordance with the international standard ISO 13528. LGC is accredited by the United Kingdom Accreditation Service (UKAS) for the provision of proficiency testing schemes against ISO/IEC 17043; a copy of our current scope of accreditation which lists the accredited schemes is available on our website: lgcstandards.com How are your PT schemes organised? The day-to-day operation of each PT scheme is the responsibility of LGC. Individual schemes are managed by a team of Scheme Coordinators, to cover reporting, customer service and technical functions. For some schemes, external advisors may also be used to provide the full range of relevant knowledge and expertise needed to operate the scheme effectively. A small number of schemes are run in collaboration with other organisations. Do you use Advisors and Advisory Groups? Yes, depending upon the PT scheme in question. Advisors are selected on the basis of their technical knowledge and experience of the industry to which the scheme is related. Advisors may be used on an ad-hoc basis and contacted when specific issues need to be addressed. Alternatively, formal Advisory Groups may be used. Advisory Groups consist of members who may or may not be participants on the scheme but who are experienced in the field of testing covered by the PT scheme. The composition and terms of reference of each Advisory Group will be agreed on a scheme-by- scheme basis. Do you run PT schemes that are jointly managed? Yes, some PT schemes are operated jointly with a partner organisation. Where schemes are operated jointly, a Management Committee may be set up to address operational issues for the scheme.

What are the fees for participation? Fees for participation are reviewed annually and the current fees for each PT scheme are available on application. Payment terms are detailed on the application form and invoice. Participants are advised that delays with payments may result in test materials and/or reports being withheld until payments are made. Where do you source your PT test materials? The vast majority of test materials are manufactured by LGC. Where this is not possible, test materials are carefully sourced to meet the needs of participants. Wherever practical, test materials will be as similar as possible to those samples routinely tested by participating laboratories. However, in some cases, in order to achieve the required degree of homogeneity and stability, test materials may be in the form of simulated matrices or concentrated spiking solutions. The analyte concentration range of test materials will usually be varied from round to round in order to be realistic and challenging. Details of individual test material types are available in the relevant scheme description. How is PT test material stability affected by time, distance and temperature? The test materials are all stable at the stated storage temperatures for at least the period of the PT scheme round. Studies have shown there is no significant difference between results of test materials tested the day after despatch and those tested on the deadline date. There is also no evidence that results are influenced by different climatic conditions of participating countries. Distance travelled does not affect test material results. We have undertaken studies on a number of our PT test materials comparing the average result according to distance travelled, and no correlations have been found. Stability consideration is an important part of the design and feasibility process for a PT scheme, where transport conditions such as temperature, humidity, pressure, exposure to x-rays etc are taken into account.



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

About the AXIO Proficiency Testing process

How do I treat my PT test material? It is important for laboratories to understand how to get the optimum benefit from PT participation. To do this, a laboratory must participate in an open and honest fashion, being prepared to, on occasion, be evaluated as unsatisfactory. If PT is to achieve its aims, laboratories need to treat the test materials the same as routine test materials, and staff must be encouraged to treat them appropriately and learn from their results in a constructive manner. Do I have to use specific methods to analyse the PT test materials? Unless otherwise instructed, participants should analyse the test materials using any method that they feel is appropriate. Participants are asked to treat the test material in the same way as a routine sample. Participants may be asked to state their method when reporting results. It is important that this information is accurate as results are analysed and reported according to the method stated. Do I have to report my results within a specific timescale? Deadlines are specified for the return of results, to ensure the timely issue of assigned values and reports to participants. For each PT scheme a closure date will therefore be specified. For certain tests there may also be a date specified by which examination of the test material is recommended to have been commenced. This is to ensure that sufficient time is available to complete the test and report results in time for the deadline date.

How do I join a PT scheme? Participants are advised to take part in the PT scheme(s) that are most fitting to their own area of testing. Where necessary, appropriate staff at AXIO Proficiency Testing can advise on which scheme is most suitable for participants. For each scheme, a scheme description and application form will be available, containing information about the test materials included in the scheme, and the intended distribution dates. This information is available on our website: lgcstandards.com/AXIO Participants are invited to place orders via our webshop at lgcstandards.com/pt by selecting which test materials they wish to receive in the PT scheme year. Alternatively, it is possible to complete an application form. Once a completed webshop order or application form is received, an order confirmation will be sent to the participant, confirming the test materials selected and distribution date. How often do I need to participate? The frequency that a laboratory needs to participate in proficiency testing depends on a wide range of factors specific to each individual laboratory, such as other quality tools used, the volume of work undertaken and the risk associated to the measurements. Therefore every individual laboratory may have a different need, which is why PT schemes provided by AXIO Proficiency Testing offer flexible participation, although some do have a minimum participation level. Third parties, such as regulatory bodies, may recommend minimum levels of participation. To gain the benefit from trend analysis, participation in a minimum of four rounds over a scheme year is normally recommended. How are PT test materials packaged and transported? Test materials are packaged appropriately to protect the contents during transit. The majority of test materials are sent using priority courier. Overseas customers must provide relevant documents to prevent delay in customs such as import permits and may be required to pay import duties locally. Once packages have been delivered, AXIO Proficiency Testing cannot be held responsible if they subsequently fail to reach the correct personnel or are not stored under the recommended conditions. Participants are asked to check the contents of packages immediately on receipt and to contact AXIO Proficiency Testing if there are any problems with the condition of the test materials or accompanying documentation.


About AXIO Proficiency Testing schemes

How should I report my results using PORTAL? For the majority of PT schemes, results are returned through our bespoke electronic reporting software, PORTAL. Once you are ready to report your results, please go to: portal.lgcstandards.com You will need to log in using your lab ID, username and password. We advise that prior to using PORTAL you read the user guide which is available at: portal.lgcstandards.com select ‘help’ from the menu. If you require further assistance please contact our support team: Tel: +44 (0)161 762 2500 Email : ptsupport@lgcgroup.com or your local LGC office. For some schemes (or parts of a scheme) alternative reporting mechanisms are provided, details of which will be emailed to participants prior to test materials receipt. It is recommended that results and calculations are checked thoroughly before reporting. Results should be reported clearly, in the format and units detailed in the scheme description. If calculations are used, unless instructed otherwise, the laboratory is to report only the final calculated result. In general, results of zero should not be reported; results should be reported depending upon the detection limit of the method used, for example, <10. The exception is a small number of parameters, where it may be appropriate to report a result of zero, depending on the measurement scale being used. Results of zero and truncated results, such as < or > cannot often be included in the data analysis and therefore allocated a performance score. Results will be rounded up or down to the number of reporting decimal places stipulated in the scheme description and may not therefore be identical to your original reported result. The effects of rounding may also mean that occasionally percentage totals do not add up exactly to 100%. Part of the challenge of proficiency testing is the ability to perform calculations and transcribe results correctly. The proficiency testing team cannot interpret or calculate results on participants’ behalf. Once submitted and received, results cannot be amended and no changes can be made after the report has been issued. However, if you notice an error in your result before the reporting deadline, this can be corrected using PORTAL until the round closes.

How many results may I submit? Although it is desirable for participants to submit multiple results in order to compare results between different analysts, methods or instruments, a single laboratory reporting a large number of results could potentially bias the dataset. In order to minimise the effects of bias, AXIO Proficiency Testing therefore limits the number of results participants are able to report. Each participant is able to enter up to 13 different results. Of these results a maximum of 3 results can be ‘nominated’. Nominated results are included in the statistical analysis of the dataset whilst non-nominated results are not, however all results will receive z performance scores and assessments as appropriate. Nominated results must be obtained using different methods, again to minimise the effects of bias. Further information is available in the PORTAL User Guide and the PORTAL Nominated Results FAQ, both of these documents are available for download from the PORTAL website and further information is available from ptsupport@lgcgroup.com Can my results be included in the report if I’ve missed the deadline for reporting? Participants are asked to return results by the given deadline in order to ensure that their results are included in the statistical analysis and the scheme report. Results received after the closure date will not be included in the report. For PT schemes where a generic report is issued, this is available to all participants subscribing to the round regardless of whether their results were submitted or not. Are microbiology results obtained from MPN methods comparable to those obtained using plate count methods? MPN and plate counts are both estimates of the number of microbial cells in the original test material and therefore provided all dilutions and calculations have been performed correctly, results should be comparable. For QWAS and QMS, comparing MPN results against results obtained from all other methods show no significant differences.



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

About reporting and evaluating results

Can I use PT data to estimate my measurement uncertainty? It is possible, but must be regarded as a very rough estimate, and is not an approach addressed in many guides to evaluating measurement uncertainty. However documents that do address the use of PT data are: • EURACHEM/CITAC Guide ‘Quantifying Uncertainty in Analytical Measurement’ (available at www. eurachem.org) • NORDTEST Report TR 537 ‘Handbook for Calculation of Measurement Uncertainty in Environmental Laboratories’ • ISO 19036 ‘Microbiology of Food and Animal Feeding Stuffs - Guidelines for the Estimation of Measurement Uncertainty for Quantitative Determinations’. What is the Standard Deviation for Proficiency Assessment (SDPA)? The SDPA expresses the acceptable difference between the laboratory result and the assigned value. An acceptable z performance score represents a result that does not deviate from the assigned value by more than twice the SDPA. The method used to determine the SDPA may vary depending upon the particular PT scheme and test material and is detailed in the relevant scheme description. A fit for purpose value for SDPA, rather than being derived from participant results, is preferable as this enables z scores to be compared from round to round to demonstrate general trends. For each scheme, the value of SDPA and the method used to derive it is reported in the scheme description and/or report.

How is the assigned value established? ISO 13528: ‘Statistical Methods for use in Proficiency Testing by Interlaboratory Comparisons’ sets out how the assigned value and performance assessment criteria can be established and describes the options for the various performance scoring systems. The assigned value is the value selected as being the best estimate of the ‘true value’ for the parameter under test. The method used to determine the assigned value may vary depending upon the particular PT scheme and test material and is detailed in the relevant scheme description. For quantitative tests, where it is appropriate, practicable and technically feasible, the assigned value will be derived through formulation (or occasionally through the use of a certified reference material) to provide metrological traceability; the associated uncertainty of the value can therefore be estimated. However, in many cases the use of a consensus value is the only practicable and technically feasible approach to use. When the assigned value is determined from the consensus value of participant results, or from expert laboratories, robust statistical methods are used for calculation of the consensus value, the estimated standard uncertainty and the robust standard deviation. For qualitative tests, participant results are compared against the intended result (assigned value) based on formulation or expert assessment. For interpretive schemes where the result is subjective rather than quantifiable, a model answer produced by appropriate experts will be published in the report. For microbiology test materials, all participant results are transformed by converting them to log10 before the statistical analysis is undertaken. How do I evaluate measurement uncertainty? The aim when evaluating measurement uncertainty is to combine the effects of all the errors that will influence the measurement result, into a single value. There are many different guides available which provide advice on evaluating measurement uncertainty. There are two specific guides that are internationally recognised: • ISO (BIPM, IEC, IFCC, IUPAC, IUPAP and OIML) ‘Guide to the Expression of Uncertainty in Measurement’ • EURACHEM/CITAC Guide ‘Quantifying Uncertainty in Analytical Measurement’ (available at: www. eurachem.org). Further information on approaches to evaluating measurement uncertainty may also be available from your national accreditation body.


About reporting and evaluating results

What standard deviation for proficiency assessment (SDPA) is used in microbiology PT schemes? There are many sources of variation in microbiological testing and the SDPA used to assess performance therefore needs to be fit-for-purpose and take all possible sources of variation into account. From experience and historical data, AXIO Proficiency Testing uses a fixed SDPA value of 0.35 log10 for the majority of microbiological tests. How do I report a ‘presumptive’ result in microbiology? Report your result as usual but record in the comments section that the result is ‘Presumptive’. What is the purpose of scoring my result? Once the assigned value for the parameters under test has been established, participant laboratories are assessed on the difference between their result and the assigned value, with this difference being represented by a performance score called a z score. This provides a simple and consistent measure of performance which is the key to monitoring competence and implementing an improvement programme as required. How is a z score calculated? The participant’s result, x, is converted into a performance score (z score) using the following formula: z = (x - X) SDPA Where: X = the assigned value SDPA = Standard Deviation for Proficiency Assessment For small data sets, there will be increased uncertainty around the assigned value if derived from a consensus value from participants’ results. In such cases, performance scores may not be provided, or may be given for information only. The z score expresses performance in relation to the assigned value and the standard deviation for proficiency assessment (SDPA). A z score of 2 represents a result that is a distance of 2 x SDPA from the assigned value.

How do I interpret my results? For quantitative examinations, participant performance is assessed using the z score, and the following interpretation is given to results: |z| ≤ 2.00 Satisfactory result 2.00 < |z| < 3.00 Questionable result |z| ≥ 3.00 Unsatisfactory result For qualitative examinations or semi-qualitative results, laboratories reporting the assigned result or range of results will be considered correct, and therefore have satisfactory performance. What are the advantages of using a z score to assess performance? • Results can be expressed in a form that is easy to interpret and understand. • Results can be summarised in graphical or tabular form to depict overall performance. • A z score allows participants to directly compare their own result with others. • If consistent statistical values are applied, a z score enables participants to monitor and trend their own performance over time. It is important to interpret any performance score in the full context of the overall results and in the context of a laboratory’s own quality control measures.



LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

About reporting and evaluating results

What is the estimated uncertainty of the assigned value? The assigned value has a standard uncertainty (ux) that depends upon the method used to derive the assigned value. When the assigned value is determined by the consensus of participants’ results, the estimated standard uncertainty of the assigned value can be calculated by: ux = 1.25 x Robust standard deviation/ √ n Where n = number of results When the assigned value is determined by formulation, the standard uncertainty is estimated by the combination of uncertainties of all sources of error, such as gravimetric and volumetric measurements. If ux is ≤ 0.3 x SDPA, then the uncertainty of the assigned value can be considered negligible and need not be considered in the interpretation of results. If ux is > 0.3 x SDPA, then the uncertainty of the assigned value is not negligible in relation to the SDPA and so z’ (z-prime) performance scores, which take into account the standard uncertainty of the assigned value in their calculation, will be reported in place of z scores. How is a z’ (z-prime) score calculated? A z’ score incorporates the standard uncertainty of the assigned value and is calculated as follows: z’ = (x - X) √ ( SDPA 2 + U x 2 ) Where x = participant result X = the assigned value SDPA = Standard Deviation for Proficiency Assessment ux = standard uncertainty of the assigned value X A z’ score is interpreted in exactly the same way as a z score, ≤2 is satisfactory, >2 but <3 is questionable and ≥3 is unsatisfactory.

Do you include outlying results due to ‘errors and blunders’ in the statistical analysis of the data? Although robust estimators are used in order to minimise the influence of outlying results, extreme results or results that are identifiably invalid should not be included in the statistical analysis of the data. For example, these may be results caused by calculation errors or the use of incorrect units. However, such results can be difficult to identify by the PT provider. For this reason, the robust mean and standard deviation will be calculated in the usual way, but those results that are out of the range of the assigned value ± 5 x SDPA will be excluded and the robust mean and standard deviation will then be recalculated. These recalculated values will be used for the statistical analysis. By removing these ‘blunders’ from the dataset any influence on the summary statistics is minimised. All results, including excluded results, will be given performance scores. How can I graphically plot and analyse trends for qualitative results? Qualitative results are difficult to depict graphically as they are not normally allocated a performance score. However for qualitative results, a correct result could be allocated a performance score of 0 to represent a satisfactory result. A false positive result can be represented by a performance score of + 3, whilst a false negative result can be represented by a performance score of - 3. If plotted graphically over time, this should give a clear visual indicator of Following statistical evaluation of the results, the reports will generally be available on the website within 4 to 10 working days of round closure (see specific scheme description). We aim to provide 95% of our reports to participants within 5 working days. Participants will be emailed when the report is available. The content of reports vary from scheme to scheme but include details of the composition of test materials, the assigned values, and tabular and / or graphical representations of participants’ results. performance in qualitative tests. How will I receive my report?


About reporting and evaluating results

My results have not been included in the report. Can I calculate my performance score (z or z’ score)? To calculate your performance score please visit: portal.lgcstandards.com Select ‘submit results’ from the menu.

How do I assess the reproducibility standard deviation from the PT report? The robust standard deviation provided in the PT report for a specific method can be taken as an estimate of the reproducibility standard deviation for the PT round for that specific method. Can I have a report that only includes my group laboratories? Yes, we can produce reports tailored to a customer’s specific requirement. There may be an additional charge for administration and computer programming costs.

About privacy and confidentiality

How do you prevent collusion and falsification of results?

Can you guarantee my laboratory’s confidentiality? In order to ensure confidentiality, participants in all PT schemes are allocated a unique laboratory reference number. This number enables results to be reported without divulging the identities of participant laboratories. Only staff within the proficiency testing team and the laboratory itself will know this number.

It defeats the objective of taking part in proficiency testing if participants are not returning genuine results. Certain measures are built into the PT schemes to try and prevent collusion but, ultimately the responsibility rests with each participating laboratory to behave in a professional manner.


LGC AXIO Proficiency Testing - 2023 Water & Environmental Catalogue

About Driving Quality Together

How can I measure my laboratory’s performance over time?

What could be the cause of my poor performance? A single poor result is not indicative of overall laboratory performance but neither is a single good result. Ideally, PT results should be monitored over time to detect potential bias or repeated unsatisfactory results. There are many possible reasons for a single poor result. It is therefore important to interpret the results from PT schemes within the context of an all- round quality assurance programme, including internal quality control, use of validated methods and reference materials. There are numerous potential causes of poor performance in a PT scheme which may include analytical and non-analytical errors. Analytical errors • Calibration / instrument problems • Extraction / clean-up • Interferences / matrix effects • Diagnostic kits / reagents • Analyst / method performance Non-analytical errors

You can do this by trend analysis. A single result simply reflects the performance of the laboratory on the particular day that the test was carried out and therefore gives limited information. Frequent participation in PT schemes over time can give greater insight into long-term performance and can help identify where internal bias may be occurring. One of the best methods of summarising performance scores over time is graphically as this gives a clear overview and is less prone to misinterpretation than numerical methods. Participants are therefore advised to monitor their PT results over time. An online trend analysis tool is included in the cost of your PT participation with AXIO Proficiency Testing. The online tool is built into the PORTAL reporting system and allows you to quickly plot your results over a range of rounds and easily download the charts for further circulation. More information regarding interpretation and trend analysis of proficiency testing results is given in the Eurachem guide on ‘Selection, Use and Interpretation of Proficiency Testing (PT) Schemes’ (available at www. eurachem. org) and ISO 13528. How can I receive advice and feedback? Communication with participants will be carried out through PT scheme-related documentation, emails, letters, or through local LGC offices. Open meetings may also be organised and all interested parties invited to attend. How can I send feedback? Comments on any aspect of our products and services are welcome either by phone, letter, email or by contacting your local LGC office.

• Calculation / transcription • Reporting format / units • Poor / incorrect storage • Test material defects

Test materials are subjected to rigorous quality control testing before being distributed to participants, and are unlikely to be the cause of a poor performance score. All possible reasons for a poor performance should be investigated fully in order to identify the most likely cause and to enable action to be taken to prevent recurrence. Repeat test materials are available after every distribution, but it is most important to investigate and understand the reason(s) for the failure, document this fully, and carry out corrective actions before repeating a test.

Can I suggest a PT scheme or test material? We welcome suggestions any time. Please complete the ‘Wish list’ form on our website: lgcstandards.com/AXIO


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