Ringonderzoeken: het aanbod is groot. Hoe kiest u?

Ringonderzoeken: het aanbod is groot. Hoe kiest u? Michel van Son – NMi VSL

Eurachem symposium ‘Afrekenen op ringonderzoeken’, 11 november 2004

Nederlands Meetinstituut Van Swinden Laboratorium • Beheer en ontwikkeling nationale meetstandaarden, kalibraties, consultancy: – massa, kracht en druk, lengte en volume, elektromagnetisme, tijd, temperatuur, ioniserende en niet-ioniserende straling, radiometrie en licht, en chemische metingen. – NEN-EN-ISO/IEC 17025 accreditatie

• Sectie Chemie

– Referentiematerialen, certificering en kalibraties: gasmengsels, dampen, elektrolytische geleidbaarheid, metaalgehaltes – Consultancy op het gebied van chemische metingen (meetonzekerheid) – Organisatie ringonderzoeken

2004-11-15

NMi - the Art of Measurement

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Inhoud

• Wat is beschikbaar?

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• Wat is een geschikt ringonderzoek? • Welk beschikbaar ringonderzoek is geschikt?

2004-11-15


Wat is beschikbaar? (1) • Collega laboratoria • Accreditatie organisaties 4

• Organisators van PTS • Tijdschriften (Aqual, ….) • Zoektocht op het WWW: proficiency test, interlaboratory comparison, laboratory evaluation study, round robin, cross check program, correlation program, co-operative trial, cross reference service, Ringversuch, ringonderzoek, ……… 2004-11-15


Wat is beschikbaar? (2) • Overzichten op het WWW ‒ Asian Pacific Laboratory Accreditation Cooperation (APLAC) – Proficiency Directory www.aplac.org/documents/documents.htm

~60 organisators –

South African National Accreditation System (SANAS) – Proficiency Testing Register www.sanas.co.za/ptr/index.php

~350 schema’s –

European Proficiency Testing Information System (EPTIS) www.eptis.bam.de

~800 schema’s 2004-11-15


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Wat is een geschikt ringonderzoek?

• Relevantie ‒Zijn er wezenlijke verschillen met de eigen praktijk?

• Kwaliteit ‒Zijn de resultaten goed bruikbaar voor de beoordeling van de kwaliteit van het lab?

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Relevantie ringonderzoek Checklist: Analyse Spoorelementen in voedingsmiddelen Proficiency test Trace Element (BIPEA, Frankrijk) Situatie in lab

Situatie in PT

Frequent bepaalde bestanddelen: Bestanddelen: As, Cd, Cr, Cu, Hg, Pb, Se, Zn Al, As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Zn

Ja/Nee

Frequent geanalyseerde monsters: rijstmeel, sojameel

Type monster: meel

Ja/Nee

Methodes toegepast: ICP-MS na zure ontsluiting

Voorgeschreven methode: Geen

Ja/Nee

Type laboratorium: Type deelnemers: Producent van voedingsmiddelen Open voor ieder lab

Ja/Nee

…………….:

Ja/Nee

…………….: Slot conclusie: PT relevant?

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Acceptabel verschil?

Ja/Nee


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Kwaliteit ringonderzoek (1) • Doelen van het laboratorium

‒ Demonstratie competentie ‒ Monitoren kwaliteit (verbeteringen, vaststellen trends) 8

• Het laboratorium rekent op ‒ Onafhankelijke en eerlijke evaluatie ‒ Technische en statistische competentie van organisator ‒ Goede kwaliteit test items (homogeniteit en stabiliteit) ‒ Nauwkeurige data invoer en -evaluatie ‒ Geheimhouding ‒ Adequate correspondentie 2004-11-15


Kwaliteit ringonderzoek (2) • ISO Guide 43-1:1997

‒ Definieert “proficiency testing”

‒ Basisdocument voor het ontwerpen van ringonderzoeken

• ILAC G13 (2000) ‒ Criteria voor de competentie van PT organisatoren ‒ Gebaseerd op ‒ ISO/IEC 17025:1999 ‒ ISO Guide 43

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Beschikbaar ringonderzoek geschikt?

• Accreditatie

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• Informatie bij collega laboratoria • Documentatie opvragen bij organisator • EPTIS database

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EPTIS database (1)

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EPTIS database (2)

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EPTIS database (3) Summary for the PTS "VIO XX-01 and VIO XX-18 (heavy) metals in drinking water" Sets of products

Food and drink Water

Testing fields

Analytical chemistry Test item

Tested property Testing method

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Drinking water Arsenic Drinking water Boron Drinking water Cadmium Drinking water Nickel Drinking water Lead Drinking water Copper Drinking water Zinc Drinking water Aluminium Drinking water Barium Drinking water Antimony Drinking water Selenium Drinking water Mercury Drinking water Manganese Drinking water Iron Drinking water Chromium

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EPTIS database (4) Relation of the PTS to specific standards, guidelines, ... Subsidiary aims of the PTS Independent Review Year of first execution Performed regularly

yes

-- If regular, frequency of performance

twice per year (total)

-- If not regular, year of last execution -- If not regular, will further PTS be performed on request Liable to pay the costs

yes

Participation fees

On request

Commissioned by This EPTIS database entry was entered / updated at

Address of the provider of the PTS KIWA Water Research P.O. Box1072

17-DEZ-03

Contact person Marieke ten Broeke

E-mail: [email protected] NL-3430 BB Nieuwegein Telephone-No.: +31 30 6069511 Telefax-No.: +31 30 6061165 WWW-Address: http://www.kiwa.nl 2004-11-15


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EPTIS database (5) Conditions for participation [Top] Participants are:

International

Number of participants:

13

Conditions for participation:

Open participation for any laboratory. Voluntary participation for all laboratories.

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Documentation and Quality Management system [Top] Quality Management system:

The QMS for the operation of the proficiency testing scheme is based on ISO/IEC Guide 43

Quality Manual and / or A complete description of the operation of the proficiency testing Standard operating procedures schemes is available. (SOP), working instructions for the operation of the PT scheme: Information material or others:

Written information material describing the proficiency testing scheme, its aim and operation are available for interested parties.

Advisory / steering group:

An advisory/steering group is involved in matters concerning the supervision and operation of the proficiency testing scheme.

Complaints:

A documented procedure for the handling of complaints is available.

Confidentiality about results of participants:

Is guaranteed

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EPTIS database (6) Characterisation of test item(s) [Top] Producer of test item(s): Determination of the assigned Value:

By the preparation process of the test items (e.g. weighing value,...).

Uncertainty of result:

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Test item management:

The different participants simultaneously receive test items, which are similar as far as possible.

Stability of test items:

Guaranteed on the basis of knowledge and experience.

Homogeneity of test items:

Homogeneity testing is carried out before the delivery of similar test items.

Means of distribution of test items:

Dispatching of the test items.

Specific requirements on packaging, dispatch and storage:

No requirements necessary.

Spare test items during PT scheme round:

Some test items are left at the provider until the end of the evaluation of the proficiency testing scheme.

Availability of test items after completion of the PT-scheme:

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EPTIS database (7) Evaluation of test results and assessment of the laboratories [Top] Statistical analysis of testing results: Handling of outliers: Performance assessment of laboratories:

Criteria for evaluation of performance: Measures used for performance assessment:

Performed according to a statistical procedure elaborated by the provider. During the evaluation of results the following statistical methods are used in order to minimise the influence of outliers: DIXON / VEGLIA The assessment of the laboratories is performed for each round of the proficiency testing scheme and based on the internal dispersion for the laboratories (precision). and based on the deviation from the assigned value (trueness).

Z-scores are used as statistical criteria in the assessment of the laboratories.

Communication between provider and participants [Top] Instructions about PT-scheme: Reporting of test results and their format: Time scale for reporting of test results: Submission of PT-results by provider: Discussion forum: Assistance for performance improvement 2004-11-15

The participants receive instructions for the handling of the test items and, where necessary, for the performance of the test(s). According to the instructions of the provider. 2-4 WEEKS 2 week(s) after receipt of results, the provider publishes a report or information about the outcome of the proficiency testing scheme. A discussion forum between the provider and the participants takes place. The participants can ask the provider for technical instruction to help for the improvement of their performance.) NMi - the Art of Measurement

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COEPT • Verschillen in uitvoering and evaluatie -> Verschillen in resultaten? • Comparability of the Operating and Evaluation Protocols of European Proficiency Testing Schemes in the Chemistry Sector ‒ Ringonderzoek van ringonderzoeken ‒ Water, voeding, milieu, arbeidshygiëne

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Samenvattende conclusies • Beschikbaarheid ringonderzoeken op vele manieren te achterhalen • EPTIS database is daarbij een goed hulpmiddel • Ook bij het opstellen van een checklist van kwaliteitsaspecten

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• Eurachem Guide on Selection, Use and Interpretation of PT Schemes • www.eurachem.nl

2004-11-15

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Ringonderzoeken: het aanbod is groot. Hoe kiest u?

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