1.1 本规程涵盖了使用标准回归技术和来自实验室间研究的数据来确定测试方法的定量下限。该确定的下限代表数值极限，在该数值极限或以上，本实践认为测试结果对商业或监管活动具有定量意义。本标准将其定义为 试验方法的混合定量限（PLOQ） . 1.2 本规程适用于能够产生接近于零的数值试验结果的试验方法。例如，定量测定接近零的分析物浓度的试验方法。 ====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至零浓度时获得的标准偏差的十倍 0 )基于浓度接近零的样品，建议使用。 3. 该定量限下的测试结果不确定度为±30 % 在99 % 信心水平。 5.1.1 本规程使用回归技术，使用ILS数据中多个操作员/实验室/样品的统计汇总重复性标准偏差，确定测试方法（PLOQ）的类似极限。该PLOQ可用于工业评估试验方法的可靠性，或比较不同试验方法的可靠性，以在接近零的浓度下进行定量测量。同样，对于PLOQ或低于PLOQ的水平，使用测试方法获得的定量测试结果在95%置信水平下的不确定性为±30%或更大。 5.1.2 本规程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 应注意的是，由于不同实验室之间的重复性测试能力可能存在差异，因此，在单个实验室测定的LLOQ可能不同于为测试方法测定的PLOQ。 5.2 在这种实践中，低于PLOQ的值被认为太不确定，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. ====== 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.