1.1 本规程包括使用标准回归技术和实验室间研究的数据来确定测试方法的定量下限。这个确定的下限代表了数值极限，在该数值极限或以上，测试结果被认为对商业或监管活动具有定量意义。本标准将其定义为 试验方法的合并定量限（PLOQ） . 1.2 本规程适用于能够产生接近于零的数值测试结果的测试方法。示例是那些定量测定接近零的分析物浓度的测试方法。 1.3 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 背景- 在单个实验室中，定量限LOQ等于在重复性条件下外推到零浓度（s 0 )基于接近零浓度的样品，已被推荐。 3. 该定量限下的测试结果的不确定度为±30 % 在99 % 置信水平。 5.1.1 本规程使用回归技术来确定试验方法（PLOQ）的类似限值，该方法使用ILS数据中多个操作员/实验室/样本的统计汇总重复性标准偏差。工业界可以使用PLOQ来评估测试方法的可靠性，或者比较不同测试方法的可信度，以便在接近零的浓度下进行定量测量。同样，工业界预计，使用PLOQ或以下水平的测试方法获得的定量测试结果的不确定度为±30 % 或在95 % 置信水平。 5.1.2 本实践中描述的回归技术也可用于确定单个实验室的定量限（LLOQ）。本标准将一个实验室的定量限定义为实验室定量限（LLOQ）。 5.1.3 需要注意的是，由于不同实验室之间可能存在重复性测试能力的差异，因此，在单个实验室确定的LLOQ可能与为测试方法确定的PLOQ不同。 5.2 这种做法认为，低于PLOQ的值太不确定，无法在商业或监管活动中有意义地使用。

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. ====== 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 (s 0 ) 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.