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GB/T 27420-2018: Conformity assessment -- Application guide for evaluation and expression of uncertainty in biological sample measurement
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Conformity assessment -- Application guide for evaluation and expression of uncertainty in biological sample measurement
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Basic data | Standard ID | GB/T 27420-2018 (GB/T27420-2018) | | Description (Translated English) | Conformity assessment -- Application guide for evaluation and expression of uncertainty in biological sample measurement | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | A00 | | Classification of International Standard | 03.120.20 | | Word Count Estimation | 62,652 | | Date of Issue | 2018-05-14 | | Date of Implementation | 2018-12-01 | | Regulation (derived from) | National Standards Announcement No. 6 of 2018 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 27420-2018: Conformity assessment -- Application guide for evaluation and expression of uncertainty in biological sample measurement
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Conformity assessment--Application guide for evaluation and expression of uncertainty in biological sample measurement
ICS 03.120.20
A00
National Standards of People's Republic of China
Evaluation of Measurement Uncertainty of Conformity Assessment Biological Samples
And presentation application guide
Published on.2018-05-14
2018-12-01 implementation
State market supervision and administration
China National Standardization Administration issued
Content
Foreword III
Introduction IV
1 Scope 1
2 Normative references 1
3 Terms and Definitions 1
4 conventions and symbols 6
5 Measurement Overview 6
5.1 Metrological traceability of measurement results 6
5.2 Uncertainty of measurement results 6
6 Measurement uncertainty measurement method 7
6.1 Overview of assessment methods 7
6.2 Class A and Class B assessment of measurement uncertainty components 8
6.3 Synthesis uncertainty and representation 9
7 Uncertainty evaluation and representation of measurement results of reference measurement procedures 10
7.1 Requirements for measurement uncertainty assessment 10
7.2 Potential sources and control requirements for measurement uncertainty 10
7.3 Measurement uncertainty assessment strategy 11
7.4 Measurement results and uncertainty representation 11
7.5 Review of the measurement uncertainty program 12
8 Uncertainty evaluation and representation of measurement results of routine measurement procedures 12
8.1 Requirements for measurement uncertainty assessment 12
8.2 Potential sources and control requirements for measurement uncertainty 12
8.3 Measurement uncertainty assessment strategy 13
8.4 Measurement results and uncertainty representation 13
8.5 Review of the measurement uncertainty procedure 14
Appendix A (informative) Conventions and symbols used in this standard 15
Appendix B (informative) Commonly used inclusion probability p value, inclusion factor k value and t value 19
Appendix C (informative) Calculation of the degree of freedom of the standard uncertainty component of Class B assessment 21
Appendix D (informative) Example of measurement uncertainty assessment 22
Reference 55
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard is proposed and managed by the National Certification and Accreditation Standardization Technical Committee (SAC/TC261).
This standard was drafted. China National Accreditation Center for Conformity Assessment, Beijing Aerospace General Hospital, Nantong University Affiliated Hospital, Shenzhen Entry and Exit Inspection
Inspection and Quarantine Bureau, China Institute of Metrology, Beijing Medical Device Inspection Institute, Shanghai Clinical Laboratory Center, National Environmental Analysis Test
Xin, Beijing Institute of Technology, Aussie Analytical Testing (Shanghai) Co., Ltd., Beijing Continental Star Quality Certification Center Co., Ltd., Zhongsheng North Control
Biotechnology Co., Ltd., Shanghai Fosun Long March Medical Science Co., Ltd.
The main drafters of this standard. Lu Jing, Chen Baorong, Wang Huimin, Dong Fuyin, Shi Guanghua, Sun Huiying, Ji Youyan, Wang Jun, Li Yuwu, Yang Yuanhua,
Shi Changyan, Ju Yi, Zhou Taogeng, Jiang Fang, Jiang Lin, Wu Jie.
Introduction
The complete measurement results should include information that characterizes the dispersion of the results, ie measurement uncertainty, which has become a consensus in the measurement field.
Used for the measurement of biological samples. An understanding of the measurement uncertainty helps to more accurately interpret and apply the measured values, especially when the measured values are
When a certain decision limit is close, at the same time, measurement uncertainty is also an important indicator of measurement quality.
At present, the basic document of the internationally announced uncertainty assessment is the Guide to Measurement Uncertainty (ISO /IEC Guide 98-3.
GuidetotheExpressionofUncertaintyinMeasurement, GUM..1995), GUM explains in principle that the measurement is not
The degree of certainty and its principle of assessment. Common methods include. bottom-up methods, top-down methods, and Monte
Carlo method. Biological sample measurements have more complex sources of uncertainty, such as imperfect definition of analytes, unstable samples, and inability to trace
Source to SI unit, measuring the "activity" of the substance, complex matrix, and usually taking the value of a single measurement in the field of medical inspection as a result
Etc., which leads to the uncertainty of assessing the measurement results of biological samples. In actual work, it is difficult to meet the method requirements as easily as chemical analysis.
The ideal conditions or their complexity are in conflict with the detection needs. This standard is based on the classification of biological sample metrology traceability, according to the conventional
The different characteristics of the measurement method and the reference measurement method, and the strategies, methods and steps for the uncertainty assessment that can be taken under different conditions are given.
Application guide.
The content of this standard mainly relates to the uncertainty assessment of biological sample measurement process, without involving biological variation, pre-measurement and post-measurement.
The effect of the process on the dispersion of results, and this does not mean that they are not important. In order to better explain and utilize the measurement results, the laboratory should combine practical work.
Make a demand, focus on its potential impact on the outcome, and explore ways to properly control and express its impact.
Evaluation of Measurement Uncertainty of Conformity Assessment Biological Samples
And presentation application guide
1 Scope
This standard is an application guide for the assessment and presentation of the uncertainty of quantitative measurements of biosourced samples in the field of conformity assessment.
This standard applies to the assessment of the uncertainty of test results related to the measurement process, but does not include biological variation, pre-measurement and post-measurement.
The effect of the process on the measurement results.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 8170 Numerical Rounding Rules and Representation and Determination of Limit Values
GB/T 19702 Description of the reference measurement procedure for the measurement of the amount of biological samples of in vitro diagnostic medical devices
GB/T 21415 in vitro diagnostic medical device biological sample medium quantity measurement calibrator and control substance evaluation
Source
GB/T 21919 Requirements for Laboratory Medical Reference Measurement Laboratory
GB/T 22576 Medical laboratory quality and capacity requirements
General requirements for GB/T 27025 testing and calibration laboratory capabilities
GB/T 27407 laboratory quality control using statistical quality assurance and control chart technology to evaluate the performance of analytical measurement systems
GB/T 27411 Test Laboratory Commonly Used Uncertainty Evaluation Method and Representation
ISO 80000-1 Quantity and Units Part 1. General (Quantitiesandunits-Part 1. General)
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Measured measurand
The amount to be measured.
3.2
Metrological traceability
Through the uninterrupted calibration chain specified in the document, the measurement results are linked to the reference object, and each calibration in the calibration chain will
Introduce measurement uncertainty.
3.3
Measuring principle measurementprinciple
Used as a basis for measurement.
3.4
Measurement method measurementmethod
A general description of the logical arrangement given for the operations used in the measurement process.
3.5
Measuring procedure measurementprocedure
Based on one or more measurement principles and a given measurement method, based on the measurement model and the calculations required to obtain the measurement results,
A detailed description of the amount.
3.6
Reference measurement program referencemeasurementprocedure
When calibrating or setting a standard substance, the measurement procedure used to provide the measurement results is suitable for evaluation by the same amount of other
The measurement accuracy of the measured magnitude obtained by the measurement procedure.
3.7
Primary reference measurement program primary referencemeasurementprocedure
Primary reference program primary referenceprocedure
A reference measurement procedure used to obtain measurements that are not related to the same type of measurement standard.
3.8
General measurement program regularmeasurementprocedure
The measurement procedure used to test samples, whose measurements usually require metrology traceability.
3.9
Measuring system measuringsystem
A set of one or more measuring instruments that are assembled and adapted to give a measured amount of information within a specified interval, usually including
He is equipped with devices such as reagents and power supplies.
3.10
Matrix effect
Sample characteristics that affect the measurement and measurable values independent of the presence of the analyte.
3.11
Reference material (standard sample, reference material) referencematerial; RM
Substances with specific properties that are sufficiently uniform and stable, whose properties have proven to be suitable for the intended use in measurement or nominal property inspection.
3.12
Certified reference material certified referencematerial; CRM
A document issued by an authority that provides one or more characteristics of uncertainty and traceability obtained using an effective procedure
The standard substance of the quantity.
3.13
Calibration calibration
The first step in a set of operations under specified conditions is to determine the relationship between the magnitude provided by the measurement standard and the corresponding indication.
Then, this information is used to determine the relationship between the measurement results obtained by the indication value, where the measurement value provided by the measurement standard and the corresponding indication value have inaccurate measurement.
Degree.
3.14
Measurement accuracy;accuracyofmeasurement
Accuracy
The degree to which the measured value is measured and its true value.
3.15
Measurement accuracy; truenessofmeasurement
Correctness trueness
Infinitely repeated measures the degree of agreement between the average of the magnitudes obtained and a reference magnitude.
3.16
Measuring precision measurementprecision
Precision precision
Under the specified conditions, the measured value or the degree of agreement between the measured values is repeated for the same or similar object to be measured.
3.17
Measuring repeatability measurerepeatability
Repetitive repeatability
Measurement precision under a set of repetitive measurement conditions.
3.18
Repeatability measurement condition measurementrepeatabilityconditionofmeasurement
Repeatability condition repeatabilitycondition
Same measurement procedure, same operator, same measurement system, same operating conditions and same location, and the same or similar in a short time
A set of measurement conditions that are like repeated measurements by the measured object.
Note. In chemistry, the term "intra-sequence precision measurement conditions" is sometimes used to mean "repetitive measurement conditions."
3.19
Measuring reproducibility measurementreproducibility
Reproducibility
Measurement precision under reproducible measurement conditions.
3.20
Reproducibility measurement condition reproducibilityconditionofmeasurement
Recurrence condition reproducibilitycondition
A set of measurement conditions for different locations, different operators, different measurement systems, and repeated measurements of the same or similar objects.
3.21
Precise measurement precisionmeasurementprecision
Period precision intermediate precision
Measurement precision under precision measurement conditions during a set of periods.
3.22
Preciseness measurement condition intermediateprecisionconditionofmeasurement
Period precision condition intermediateprecisioncondition
Except for the same measurement procedure, the same location, and a set of measurements that repeat measurements on the same or similar subject over a longer period of time
In addition to the quantitative conditions, other conditions involving changes may also be included.
3.23
Indoor recurrence within-laboratoryreproducibility
Measurement precision under reproducible measurement conditions in the same laboratory.
3.24
Indoor recurrence condition within-laboratoryreproducibilitycondition
Reproducible measurement conditions in the same laboratory.
Note 1. Indoor reproducibility conditions are the measurement conditions for the greatest variation in precision in the same laboratory.
Note 2. For some laboratories, there may not be multiple measurement systems, and the precision may indicate the maximum possible imprecision measurement conditions.
Note 3. Indoor reproducibility conditions and period precision conditions are not strictly defined. When applied, the description of conditions should include changed and unchanging conditions and
How much has actually changed.
3.25
Measurement error; errorofmeasurement
Error error
The measured magnitude is subtracted from the reference magnitude.
3.26
Measuring offset measurementbias
Offset bias
An estimate of the system measurement error.
3.27
Measurement uncertainty measurementuncertainty
Uncertainty
Based on the information obtained, a non-negative parameter that imparts dispersibility to the measured value is characterized.
Note 1. Measurement uncertainty includes components caused by system influences, such as components related to corrections and measurement criteria, and defined uncertainties.
Sometimes the estimated system impact is not corrected, but treated as an uncertainty component.
Note 2. This parameter can be such as the standard deviation (or its specific multiple) called the standard measurement uncertainty, or the interval half width including the probability.
Note 3. Measurement uncertainty generally consists of several components. Some of these components can be based on a statistical distribution of a series of measurements, according to the class A of measurement uncertainty.
The assessment was assessed and characterized by experimental standard deviation. Other components can be estimated based on the probability distribution of experience or other information.
The Class B assessment of certainty is assessed and also characterized by standard deviation.
Note 4. Generally, for a given set of information, the measurement uncertainty corresponds to the amount of magnitude assigned to the measurement. A change in this value will result in a corresponding inaccuracy
The change in the degree.
3.28
Standard uncertainty standarduncertainty
Standard measurement uncertainty standardmeasurementuncertainty;standarduncertaintyofmeasurement
Measurement uncertainty expressed in standard deviation.
3.29
Class A assessment of measurement uncertainty TypeAevaluationofmeasurementuncertainty
Class A assessment TypeAevaluation
The measurement uncertainty component is evaluated by the statistical analysis method for the measured value under the specified measurement conditions.
Note. The specified measurement conditions refer to repetitive measurement conditions, period precision measurement conditions, or reproducibility measurement conditions.
3.30
Class B assessment of measurement uncertainty TypeBevaluationofmeasurementuncertainty
Class B assessment TypeBevaluation
The measurement uncertainty component is evaluated by a method different from the measurement uncertainty class A assessment.
Example. The rating is based on the following information.
---The amount of authority issued by the authority;
--- The amount of certified reference material;
--- Calibration certificate;
--- Instrument drift;
--- The accuracy level of the measured measuring instrument;
--- Limit values inferred based on personnel experience, etc.
3.31
Synthetic standard uncertainty combinedstandarduncertainty
Synthetic standard measurement uncertainty combinedstandardmeasurementuncertainty
The standard measurement uncertainty of the output obtained from the standard measurement uncertainty for each input in a measurement model.
Note. In the case of input quantities related in the measurement model, the covariance must be considered when calculating the synthetic standard uncertainty.
3.32
Extended uncertainty expandeduncertainty
Extended measurement uncertainty expandedmeasurementuncertainty
The composite standard uncertainty is the product of a numerical factor greater than one.
Note 1. This factor depends on the type of probability distribution of the output in the measurement model and the selected inclusion probability.
Note 2. The term “factor” in this definition refers to the inclusion factor.
3.33
Contains interval coverageinterval
An interval containing a measured set of magnitudes determined based on the available information, the measured value falling within the interval with a certain probability.
Note 1. The inclusion interval is not necessarily centered on the selected measured value.
Note 2. The inclusion interval should not be called a “confidence interval” to avoid confusion with statistical concepts.
Note 3. The inclusion interval can be derived from the extended measurement uncertainty.
3.34
Contains probability coverageprobability
The probability of including a measured set of magnitudes within a specified inclusion interval.
Note 1. To avoid confusion with statistical concepts, inclusion probabilities should not be called confidence levels.
Note 2. The inclusion of probability in GUM is also called "level of confidence".
Note 3. The inclusion probability replaces the “confidence level” that has been used.
3.35
Include factor coveragefactor
To obtain extended uncertainty, a number greater than one that is multiplied by the synthetic standard uncertainty.
Note. The inclusion factor is usually indicated by the symbol k.
3.36
Probability distribution probabilitydistribution
Give a (random variable) function that takes a random variable to take any given value or the probability of a given set.
3.37
Distribution function distributionfunction
For each threshold, a function is given for the probability that the random variable X is less than or equal to ξ.
GX(ξ)=Pr(X ≤ξ)
3.38
Probability density function probabilitydensityfunction; PDF
The derivative of the distribution function, if the derivative exists, then gX(ξ)=dGX(ξ)/dξ, where GX(ξ) is the distribution function and X is the random variable.
3.39
Normal distribution normaldistribution
The probability distribution of the continuous random variable X, whose probability density function is
gX(ξ)=
σ 2π
Exp -
Ξ-μ
2é
Êê
Úú ,-¥< ξ< ¥
Where μ is the expectation of X and σ is the standard deviation.
3.40
t distribution tdistribution
The probability distribution of the continuous random variable X, whose probability density function is
gX(ξ)=
Γ[(ν 1)/2]
πνΓ(ν/2)
1 ξ
-(ν 1)/2
In the formula, -¥< ξ< ¥, ν represents the degree of freedom of the distribution, which is a positive integer, and the gamma function is of the form.
Γ(z)=∫
Tz-1e-tdt,z >0
3.41
Distribution propagation
A method of determining the probability distribution of the output by applying a probability distribution of the input quantities associated with the output.
4 conventions and symbols
See Appendix A for the conventions and symbols used in this standard.
5 Measurement overview
5.1 Metrological traceability of measurement results
5.1.1 Tracing to international or national standards is the basis for the comparison of measurement results.
5.1.2 The amount of some biological parameters is not yet available in metrologically recognized international or national standards. According to GB/T 21415, according to the measurement knot
The metrological traceability of fruit is divided into the following five types of measurement procedures for biological samples.
a) Type I, with a primary reference measurement procedure and a primary calibrator, can be traced to the SI unit measurement procedure;
b) Type II, with internationally agreed reference measurement procedures (non-primary) and internationally agreed calibrators, cannot be traced to SI units
Measuring procedure;
c) Type III, with internationally agreed reference measurement procedures (non-primary), no internationally agreed calibrators, not traceable to SI units
Measuring procedure;
d) Type IV, with internationally agreed calibrators (non-primary), no internationally agreed reference measurement procedures, cannot be traced to SI units
Measuring procedure;
e) Type V, no internationally agreed reference measurement procedures, no internationally agreed calibrators, and cannot be traced to SI units in measurement
program.
5.1.3 In the absence of calibrators and reference measurement procedures, the results of the alignment can be compared to the reference material of the protocol or
The mean of the protocol method.
5.2 Uncertainty of measurement results
5.2.1 The purpose of the measurement is to determine the value to be measured. The measurement result is usually only an approximation or an estimate of the measured value. Complete measurement junction
If you need to attach a statement of uncertainty with the results.
5.2.2 There are many potential factors affecting the measurement results, including but not limited to the following factors.
a) the definition of the measurement is incomplete;
b) the reproduction of the definition of the measurement is not perfect;
c) insufficient representation of the sample being measured;
d) insufficient understanding of the impact of the measurement on environmental conditions or imperfect measurement or control of environmental conditions;
e) personnel reading error;
f) limits on instrument resolution or identification thresholds;
g) the measurement standards and the magnitude of the reference materials are inaccurate;
h) the values of constants and other parameters obtained from the outside and used in the data reduction algorithm are inaccurate;
i) approximations and assumptions in measurement methods and procedures;
j) repeating the variability of the measurement process under seemingly identical conditions;
k) Factors that have not been recognized or recognized.
5.2.3 The factors affecting the measurement results are not necessarily independent of each other. For example, some factors in 5.2.2a)~i) may contribute to j).
6 Evaluation method of measurement uncertainty
6.1 Overview of assessment methods
6.1.1 The exact value of the contribution that causes the measurement result to produce an error, although unknown or unknown, but with the random effects and systems that cause the error
The uncertainty associated with the impact is measurable. Measurement uncertainty can be assessed in a variety of ways, and the assessment methods described in this document include.
Bottom-up method (hereinafter referred to as bottom-up method) (6.1.2), top-down method (hereinafter referred to as
Top-down method) (6.1.3) and Monte Carlo method (hereinafter referred to as MCM method) (6.1.4).
6.1.2 The bottom-up method focuses on how the input affects the results. The evaluation steps include.
a) The definition is measured. The accuracy of the measurement depends on the level of detail defined or specified by the measurement and is measured for the required accuracy.
The definition should be complete enough to guarantee the uniqueness of its value.
b) mathematically express the relationship between the input quantity Xi related to the measured Y and the measured Y. Y=f(X1,,XN), function
f shall contain each quantity, including all corrections and corrections for components that have a significant influence on the uncertainty of the measurement results.
factor.
c) Determine the estimated value xi of the input quantity Xi, either based on a statistical analysis of a series of observations or by other methods.
d) Evaluate the standard uncertainty u(xi) for each input estimate xi. Input estimates obtained from statistical analysis of a series of observations
For the value, u(xi) is eval...
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