GB/T 15000.5-2023 Directives for the work of reference materials - Part 5: The in-house preparation of quality control materials (QCMs)
1 Scope
This Guide outlines the essential characteristics of reference materials for quality control (QC) purposes, and describes the processes by which they can be prepared by competent staff within the facility in which they will be used (i.e. where instability due to transportation conditions is avoided). The content of this Guide also applies to inherently stable materials, which can be transported to other locations without risk of any significant change in the property values of interest.
The primary audience for this Guide is laboratory staff who are required to prepare and use materials for specific in-house quality control applications. Preparation of QCMs, where transportation is a necessary component of the supply chain, such as laboratory sites at different locations or for proficiency testing schemes, should conform to the relevant requirements of lSO Guides 34 and 35.
The description of the production of reference materials (RMs), as detailed in ISO Guide 34 and ISO Guide 35 is also applicable to the preparation of quality control materials (QCMs).However, the requirements for "in-house” QCMs are less demanding than those for a certified reference material (CRM). The preparation of QCMs should involve homogeneity and stability assessments, and a limited characterization of the material to provide an indication of its relevant property values and their variation, prior to use. This document provides the quality criteria that a material should fulfil to be considered fit-for-purpose for demonstrating a measurement system is under statistical control. Guidance on uses of such materials, for example setting up a QC chart, is adequately covered elsewhere [3], [4], [5], [6] and is not included in this Guide.
The layout and structure of this Guide provides general information on the preparation of QCMs in the main chapters, with specific case studies covering a range of sectors in the annexes. The case studies are not complete "process manuals" but are included to highlight some of the key considerations when preparing QcMs.The case studies vary in complexity and detail, including sector specific terminology, but provide a range of information for laboratory staff to draw from.
lt is expected that those involved in QCM preparation will have some knowledge of the type of material to be prepared and be aware of any potential problems due to matrix effects,contamination, etc.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies.For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3534-1 Statistics - Vocabulary and symbols - Part 1: General statistical terms and terms used in probability
Note: GB/T 3358.1-2009, Statistics - Vocabulary and symbols - Part 1: General statistical terms and terms used in probability (ISO 3534-1:2006, IDT)
ISO Guide 30 Reference materials - Selected terms and definitions
Note: GB/T 15000.2-2019, Directives for the work of reference materials - Part 2: Selected terms and definitions ( ISO Guide 30:2015, IDT)
ISO/IEC Guide 99 International vocabulary of metrology - Basic and general concepts and associated terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO Guide 30, ISO/IEC Guide 99 and ISO 3534-1 and the following apply.
3.1
indicative value
value of a quantity or property, included in the certificate of a CRM or otherwise supplied, which is provided for information only (i.e. is not certified by the producer or the certifying body)
Note: Values assigned to quality control materials (QCMs) can only be indicative in that they have no metrological traceability.lSO Guide 30:1992[7] uses the term "uncertified value" to describe a value of a quantity provided for information only.
4 Quality control materials (QCMs)
The term “quality control material" or "QCM" has been devised for the purposes of this Guide solely to simplify repeated reference to materials used routinely to assess the precision of test procedures. It is not intended to define a new class of reference materiais.Such materials are variously referred to in the open literature as "in-house reference materials", "quality control samples", "check samples", "set up samples", etc.
Where no suitable CRM exists, laboratories may use QCMs to provide an assessment of the repeatability / intermediate precision / reproducibility of a measurement result.QCMs cannot be used to establish metrological traceability or trueness of a measurement result.
QCMs should always comply with the basic requirements of any reference material, .e.they should be sufficiently homogeneous and stable with respect to the properties of interest.The level of heterogeneity should be less than the expected standard deviation of the measurement process or an established criterion value against which the assessment of laboratory performance or the "normalization” of results is acceptable. The QCM should be stable for a period of time that is at least as long as that during which it is intended to be used.
5 Applications of quality control materials (QCMs)
The principal function of QCMs is to provide laboratories with an economical means of checking their routine test procedures for precision on a regular basis (e.g.daily, weekly or monthly).
While CRMscan in all cases replace QCMs, QCMs are not replacements for CRMs; they are complementary to them having a specific, limited purpose in the measurement process.CRMs produced according to the principles of ISO Guide 34 are essential to establish the concept of metrological traceability in a meaningful manner, and provide the highest standard with respect to reference materials. There is no requirement for QCMs to have metrologically traceable assigned values; consequently, QCMs cannot be used to establish metrological traceability or to estimate uncertainty. For method validation and uncertainty estimation, QCMs may be used to a limited extent (e.g. for establishment of a precision estimate as part of the total measurement uncertainty).
Uses of QCMs include (but are not limited to):
——preparation of QC charts- to demonstrate control of a measurement process within a laboratory or to confirm the effectiveness of a laboratory's quality control process or to demonstrate control of a measurement process over a period of time;
——comparison of results (e.g. from two or more series of related samples either in a short period of time or over an extended period of time when a measurement process is known to vary);
——method development - to establish consistency (for validation a certified reference material should be used);
——instrument performance checks;
——repeatability and reproducibility studies - repeated use over an extended period of time, instruments, operators, etc., to estimate long-term reproducibility or robustness of a measurement process or laboratory;
——as check samples - for example, to confirm the degree of equivalence of measurement results from two or more laboratories (e.g.provider and user), where the materials are inherently stable;
——operator variability;
——impact of any changes to the environmental conditions (e.g.temperature, humidity).
When confirming that a measurement process is under statistical control [3], [4], [5], [6] the acceptability of laboratory performance is generally assessed by comparing either the standard deviation or the range of the individual results for the QCM against a pre-established criterion. lf a lack of control of the measurement process is identified, the laboratory needs to take action. In the simplest case, this may require repeating the "suspect"measurements, perhaps following a re-calibration of instruments.
A more in-depth discussion of the uses of quality control materials can be found in ISO Guide 33.[10]
Regardless of the intended use, it is necessary to assess homogeneity and stability of a QCM. [11]
6 Steps in the in-house preparation of quality control materials (QCMs)
The fundamental purpose of QCMs is to detect change. ln general, more pragmatic and less rigorous protocols can be used for stability and homogeneity steps to strike a balance between material development costs on the one hand and the intended use of the material on the other.
The production of any reference material requires a level of technical and organizational competence. lt is acknowledged that in many cases "in-house" QCMs will be prepared by technically competent staff that is knowledgeable about the materials/processes being used.
The key steps involved in the in-house preparation of a typical QCM are summarized in the flow chart in Figure 1 and are described in more detail in References [12] and [13]. Materials can be sourced from, processed, sub-divided and packaged by third parties, where they have specialized equipment and/or expertise. Materials may even be products which are commercially available and meet the user's specification (e.g. food products available in appropriately sized units from a single production batch).
Note： Any of these steps may be subcontracted to a technically competent subcontractor.
7 Material specification
The key criteria in the specification and selection of a QCM are for the material to be as close as possible to real samples and available in appropriate quantities.
7.1 Matrix type, matching and commutability
In general terms, the uncertainties associated with a measurement result arise from the two main stages of the measurement procedure:
——the preparation of a sample comprising digestion, extraction, clean-up, etc.;
—— the measurement of the property in the prepared sample by a suitable technique.
The scope and applicability of a matrix reference material is an important consideration for both the production and use of all reference materials.
The matrix of the QCM should be the same or as similar as possible to the matrix of the routine test samples, so that a satisfactory result for the QCM is genuinely indicative of satisfactory results for the test samples. This matrix matching requires some knowledge of the analytical procedure used on the routine samples, so that a judgment can be made as to the degree of variation of the physical/chemical properties of the sample and test matrices that may cause them to respond differently to a particular measurement procedure.
Standard
GB/T 15000.5-2023 Directives for the work of reference materials—Part 5: The in-house preparation of quality control materials（QCMs） (English Version)
Standard No.
GB/T 15000.5-2023
Status
valid
Language
English
File Format
PDF
Word Count
25000 words
Price(USD)
750.0
Implemented on
2023-8-6
Delivery
via email in 1~3 business day
Detail of GB/T 15000.5-2023
Standard No.
GB/T 15000.5-2023
English Name
Directives for the work of reference materials—Part 5: The in-house preparation of quality control materials（QCMs）
GB/T 15000.5-2023 Directives for the work of reference materials - Part 5: The in-house preparation of quality control materials (QCMs)
1 Scope
This Guide outlines the essential characteristics of reference materials for quality control (QC) purposes, and describes the processes by which they can be prepared by competent staff within the facility in which they will be used (i.e. where instability due to transportation conditions is avoided). The content of this Guide also applies to inherently stable materials, which can be transported to other locations without risk of any significant change in the property values of interest.
The primary audience for this Guide is laboratory staff who are required to prepare and use materials for specific in-house quality control applications. Preparation of QCMs, where transportation is a necessary component of the supply chain, such as laboratory sites at different locations or for proficiency testing schemes, should conform to the relevant requirements of lSO Guides 34 and 35.
The description of the production of reference materials (RMs), as detailed in ISO Guide 34 and ISO Guide 35 is also applicable to the preparation of quality control materials (QCMs).However, the requirements for "in-house” QCMs are less demanding than those for a certified reference material (CRM). The preparation of QCMs should involve homogeneity and stability assessments, and a limited characterization of the material to provide an indication of its relevant property values and their variation, prior to use. This document provides the quality criteria that a material should fulfil to be considered fit-for-purpose for demonstrating a measurement system is under statistical control. Guidance on uses of such materials, for example setting up a QC chart, is adequately covered elsewhere [3], [4], [5], [6] and is not included in this Guide.
The layout and structure of this Guide provides general information on the preparation of QCMs in the main chapters, with specific case studies covering a range of sectors in the annexes. The case studies are not complete "process manuals" but are included to highlight some of the key considerations when preparing QcMs.The case studies vary in complexity and detail, including sector specific terminology, but provide a range of information for laboratory staff to draw from.
lt is expected that those involved in QCM preparation will have some knowledge of the type of material to be prepared and be aware of any potential problems due to matrix effects,contamination, etc.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies.For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3534-1 Statistics - Vocabulary and symbols - Part 1: General statistical terms and terms used in probability
Note: GB/T 3358.1-2009, Statistics - Vocabulary and symbols - Part 1: General statistical terms and terms used in probability (ISO 3534-1:2006, IDT)
ISO Guide 30 Reference materials - Selected terms and definitions
Note: GB/T 15000.2-2019, Directives for the work of reference materials - Part 2: Selected terms and definitions ( ISO Guide 30:2015, IDT)
ISO/IEC Guide 99 International vocabulary of metrology - Basic and general concepts and associated terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO Guide 30, ISO/IEC Guide 99 and ISO 3534-1 and the following apply.
3.1
indicative value
value of a quantity or property, included in the certificate of a CRM or otherwise supplied, which is provided for information only (i.e. is not certified by the producer or the certifying body)
Note: Values assigned to quality control materials (QCMs) can only be indicative in that they have no metrological traceability.lSO Guide 30:1992[7] uses the term "uncertified value" to describe a value of a quantity provided for information only.
4 Quality control materials (QCMs)
The term “quality control material" or "QCM" has been devised for the purposes of this Guide solely to simplify repeated reference to materials used routinely to assess the precision of test procedures. It is not intended to define a new class of reference materiais.Such materials are variously referred to in the open literature as "in-house reference materials", "quality control samples", "check samples", "set up samples", etc.
Where no suitable CRM exists, laboratories may use QCMs to provide an assessment of the repeatability / intermediate precision / reproducibility of a measurement result.QCMs cannot be used to establish metrological traceability or trueness of a measurement result.
QCMs should always comply with the basic requirements of any reference material, .e.they should be sufficiently homogeneous and stable with respect to the properties of interest.The level of heterogeneity should be less than the expected standard deviation of the measurement process or an established criterion value against which the assessment of laboratory performance or the "normalization” of results is acceptable. The QCM should be stable for a period of time that is at least as long as that during which it is intended to be used.
5 Applications of quality control materials (QCMs)
The principal function of QCMs is to provide laboratories with an economical means of checking their routine test procedures for precision on a regular basis (e.g.daily, weekly or monthly).
While CRMscan in all cases replace QCMs, QCMs are not replacements for CRMs; they are complementary to them having a specific, limited purpose in the measurement process.CRMs produced according to the principles of ISO Guide 34 are essential to establish the concept of metrological traceability in a meaningful manner, and provide the highest standard with respect to reference materials. There is no requirement for QCMs to have metrologically traceable assigned values; consequently, QCMs cannot be used to establish metrological traceability or to estimate uncertainty. For method validation and uncertainty estimation, QCMs may be used to a limited extent (e.g. for establishment of a precision estimate as part of the total measurement uncertainty).
Uses of QCMs include (but are not limited to):
——preparation of QC charts- to demonstrate control of a measurement process within a laboratory or to confirm the effectiveness of a laboratory's quality control process or to demonstrate control of a measurement process over a period of time;
——comparison of results (e.g. from two or more series of related samples either in a short period of time or over an extended period of time when a measurement process is known to vary);
——method development - to establish consistency (for validation a certified reference material should be used);
——instrument performance checks;
——repeatability and reproducibility studies - repeated use over an extended period of time, instruments, operators, etc., to estimate long-term reproducibility or robustness of a measurement process or laboratory;
——as check samples - for example, to confirm the degree of equivalence of measurement results from two or more laboratories (e.g.provider and user), where the materials are inherently stable;
——operator variability;
——impact of any changes to the environmental conditions (e.g.temperature, humidity).
When confirming that a measurement process is under statistical control [3], [4], [5], [6] the acceptability of laboratory performance is generally assessed by comparing either the standard deviation or the range of the individual results for the QCM against a pre-established criterion. lf a lack of control of the measurement process is identified, the laboratory needs to take action. In the simplest case, this may require repeating the "suspect"measurements, perhaps following a re-calibration of instruments.
A more in-depth discussion of the uses of quality control materials can be found in ISO Guide 33.[10]
Regardless of the intended use, it is necessary to assess homogeneity and stability of a QCM. [11]
6 Steps in the in-house preparation of quality control materials (QCMs)
The fundamental purpose of QCMs is to detect change. ln general, more pragmatic and less rigorous protocols can be used for stability and homogeneity steps to strike a balance between material development costs on the one hand and the intended use of the material on the other.
The production of any reference material requires a level of technical and organizational competence. lt is acknowledged that in many cases "in-house" QCMs will be prepared by technically competent staff that is knowledgeable about the materials/processes being used.
The key steps involved in the in-house preparation of a typical QCM are summarized in the flow chart in Figure 1 and are described in more detail in References [12] and [13]. Materials can be sourced from, processed, sub-divided and packaged by third parties, where they have specialized equipment and/or expertise. Materials may even be products which are commercially available and meet the user's specification (e.g. food products available in appropriately sized units from a single production batch).
Note： Any of these steps may be subcontracted to a technically competent subcontractor.
7 Material specification
The key criteria in the specification and selection of a QCM are for the material to be as close as possible to real samples and available in appropriate quantities.
7.1 Matrix type, matching and commutability
In general terms, the uncertainties associated with a measurement result arise from the two main stages of the measurement procedure:
——the preparation of a sample comprising digestion, extraction, clean-up, etc.;
—— the measurement of the property in the prepared sample by a suitable technique.
The scope and applicability of a matrix reference material is an important consideration for both the production and use of all reference materials.
The matrix of the QCM should be the same or as similar as possible to the matrix of the routine test samples, so that a satisfactory result for the QCM is genuinely indicative of satisfactory results for the test samples. This matrix matching requires some knowledge of the analytical procedure used on the routine samples, so that a judgment can be made as to the degree of variation of the physical/chemical properties of the sample and test matrices that may cause them to respond differently to a particular measurement procedure.
