ASTM D6259-23

Standard Practice for Determination of a Pooled Limit of Quantitation for a Test Method

SIGNIFICANCE AND USE
5.1 Background—In a single laboratory, the limit of quantitation, LOQ, equal to ten times the standard deviation obtained under repeatability conditions extrapolated to zero concentration (s0) based on samples with close to zero concentrations has been recommended.3 A test result at this LOQ has an uncertainty of ±30 % at the 99 % confidence level.  
5.1.1 This practice uses a regression technique to determine a similar limit for a test method (PLOQ) using statistically pooled repeatability standard deviations over multiple operators/laboratories/samples from ILS data. This PLOQ can be used by industry to assess the reliability of a test method, or, compare reliability of different test methods, for quantitative measurement at concentrations near zero. Similarly, quantitative test results obtained using the test method for levels at or below the PLOQ can be expected by industry to have an uncertainty of ±30 % or greater at the 95 % confidence level.  
5.1.2 The regression technique described in this practice can also be used to determine a limit of quantitation specific for a single laboratory (LLOQ). The limit thus quantified for one laboratory is defined by this standard as the laboratory limit of quantitation (LLOQ).  
5.1.3 It should be noted that since differences in repeatability testing capabilities between different laboratories can exist, therefore, LLOQ determined at a single laboratory can be different than the PLOQ determined for the test method.  
5.2 Values below the PLOQ are deemed by this practice to be too uncertain for meaningful use in commerce, or in regulatory activities.
SCOPE
1.1 This practice covers the use of standard regression techniques and data from an interlaboratory study to determine a lower quantitative limit for a test method. This determined lower limit represents the numerical limit at or above which the test results are considered to be quantitatively meaningful for commerce or regulatory activities by this practice. It is defined by this standard as the pooled limit of quantitation (PLOQ) for the test method.  
1.2 This practice is applicable to test methods that are capable of producing numerical test results close to zero. Examples are those test methods that determine quantitatively the concentration of analyte(s) near zero.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2023
• ICS: 19.020 - Test conditions and procedures in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.94 - Coordinating Subcommittee on Quality Assurance and Statistics

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6259 − 23 An American National Standard
Standard Practice for
Determination of a Pooled Limit of Quantitation for a Test
1
Method
This standard is issued under the fixed designation D6259; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 3. Terminology
1.1 This practice covers the use of standard regression 3.1 Definitions:
techniques and data from an interlaboratory study to determine 3.1.1 repeatability conditions, n—conditions under which
a lower quantitative limit for a test method. This determined test results are obtained with the same test method in the same
lower limit represents the numerical limit at or above which the laboratory by the same operator with the same equipment in the
test results are considered to be quantitatively meaningful for shortest practical period of time using test units or test
commerce or regulatory activities by this practice. It is defined specimens taken at random from a single quantity of material
by this standard as the pooled limit of quantitation (PLOQ) for that is as nearly homogeneous as possible.
the test method.
NOTE 1—By in the shortest practical period of time is meant that the
test results, at least for one material, are obtained in a time period not less
1.2 This practice is applicable to test methods that are
than in normal testing and not so long as to permit significant change in
capable of producing numerical test results close to zero.
test material, equipment, or environment. See Terminology E456.
Examples are those test methods that determine quantitatively
3.2 Definitions of Terms Specific to This Standard:
the concentration of analyte(s) near zero.
3.2.1 pooled limit of quantitation (PLOQ), n—level of
1.3 This international standard was developed in accor-
property or concentration for a test method at which the ratio:
dance with internationally recognized principles on standard-
[10× pooled repeatability standard deviation of results for a
ization established in the Decision on Principles for the
concentration level/concentration level] = 1.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.2.1.1 Discussion—Quantitative test results obtained using
Barriers to Trade (TBT) Committee.
a test method at or below its PLOQ is expected to have an
uncertainty of 630 % or greater at the 95 % confidence level.
2. Referenced Documents
3.2.2 pooled repeatability standard deviation, n—the statis-
2
tically pooled standard deviation for results obtained under
2.1 ASTM Standards:
repeatability conditions over multiple operators/laboratories
D6300 Practice for Determination of Precision and Bias
for a sample that is obtained in accordance with Practice
Data for Use in Test Methods for Petroleum Products,
D6300 or other equivalent Interlaboratory Study (ILS) analysis
Liquid Fuels, and Lubricants
(for example, Practice E691, ISO 4259).
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to
3.2.3 laboratory limit of quantitation (LLOQ), n—level of
Determine the Precision of a Test Method
property or concentration for a test method at which the ratio:
[10× repeatability standard deviation of results for a concen-
tration level determined in a single laboratory/concentration
1
This practice is under the jurisdiction of Committee D02 on Petroleum
level] = 1.
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
mittee D02.94 on Coordinating Subcommittee on Quality Assurance and Statistics.
3.2.3.1 Discussion—Quantitative test results obtained by
Current edition approved May 1, 2023. Published May 2023. Originally
this single laboratory at or below its LLOQ is expected to have
approved in 1998. Last previous edition approved in 2019 as D6259 – 15 (2019).
DOI: 10.1520/D6259-23.
an uncertainty of 630 % or greater at the 95 % confidence
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
level.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.3 Acronyms:
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.3.1 ILS, n—interlaboratory study.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6259 − 15 (Reapproved 2019) D6259 − 23 An American National Standard
Standard Practice for
Determination of a Pooled Limit of Quantitation for a Test
1
Method
This standard is issued under the fixed designation D6259; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This practice covers the use of standard regression techniques and data from an interlaboratory study to determine a lower
quantitative limit for a test method. This determined lower limit represents the numerical limit at or above which the test results
are considered to be quantitatively meaningful for commerce or regulatory activities by this practice. It is defined by this standard
as the pooled limit of quantitation (PLOQ) for the test method.
1.2 This practice is applicable to test methods that are capable of producing numerical test results close to zero. Examples are those
test methods that determine quantitatively the concentration of analyte(s) near zero.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions:
3.1.1 repeatability conditions, n—conditions under which test results are obtained with the same test method in the same
laboratory by the same operator with the same equipment in the shortest practical period of time using test units or test specimens
taken at random from a single quantity of material that is as nearly homogeneous as possible.
NOTE 1—By in the shortest practical period of time is meant that the test results, at least for one material, are obtained in a time period not less than in
normal testing and not so long as to permit significant change in test material, equipment, or environment. See Terminology E456.
3.2 Definitions of Terms Specific to This Standard:
1
This practice is under the jurisdiction of Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee D02.94
on Coordinating Subcommittee on Quality Assurance and Statistics.
Current edition approved May 1, 2019May 1, 2023. Published June 2019May 2023. Originally approved in 1998. Last previous edition approved in 20152019 as
D6259 – 15.D6259 – 15 (2019). DOI: 10.1520/D6259-15R19.10.1520/D6259-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D6259 − 23
3.2.1 pooled limit of quantitation (PLOQ), n—level of property or concentration for a test method at which the ratio: [10× pooled
repeatability standard deviation of results for a concentration level/concentration level] = 1.
3.2.1.1 Discussion—
Quantitative test results obtained using a test method at or below its PLOQ is expected to have an uncertainty of 630 % or greater
at the 95 % confidence level.
3.2.2 pooled repeatability standard deviation, n—the statistically pooled standard deviation for results obtained under repeatability
conditions over multiple operators/laboratories for a sample that is obtained in accordance with Practice D6300 or other equivalent
Interlaboratory Study (ILS) analysis (for example, Practice E691, ISO 4259).
3.2.3 laboratory limit of quantitation (LLOQ), n—level of property or concentration for a test method at which the ratio: [10×
repeatability standard deviation of results for a concentration level determined in a single laboratory/concentration level] =
...