AOAC Guidance on FA Immunoassay Validation (August 2023)

3.1.11. Quantitative method: Method of analysis whose result is the amount (mass or concentration) of 102 the analyte. 103 3.1.12. Reference material: material, sufficiently homogeneous and stable with respect to one or more 104 specified properties, which has been established to be fit for its intended use in a measurement 105 process (ISO Guide 30:2015) 106 3.1.13. Robustness: the ability of a method to resist significant changes in the final results when 107 reasonable deviations are made in the experimental conditions described in the procedure. 108 3.1.14. Sample: A small portion or quantity taken from a population or lot that is ideally a representative 109 selection of the whole. Samples are taken from lots for purposes of scientific examination and 110 analysis and are intended to provide characteristic information about the population, generally by 111 applying statistical calculations. (ISO 3534-1:1993) 112 3.1.14.1. Test portion: Portion of the test sample as prepared for testing or analysis, where the 113 whole quantity is used for analyte extraction at one time (ISO 16577:2022) 114 3.1.14.2. Analytical sample: The material from which the test portion is selected (after 115 grinding/homogenization if necessary 116 3.1.15. Selectivity: The degree to which the method can quantify the target analyte in the presence of 117 other analytes, matrices, or other potentially interfering materials 118 3.1.15.1. Cross-reactivity: Cross-reactivity is defined as a reaction to a material other than the target 119 analyte 120 3.1.15.2. Measurement Interference: A cause of significant bias in the measured analyte 121 concentration due to the effect of another component or property of the sample which may 122 result from nonspecificity of the detection system, suppression of an indicator reaction, or 123 inhibition of the analyte. (2) An interference can be endogenous, present in the sample, or 124 exogenous, introduced into the sample during the measurement process. 125 3.1.16. Technical replicate: One extracted test portion is analyzed more than one time 126 Note 1 to entry: Example for two technical replicates: An extract from a single test portion is 127 measured instrumentally multiple times. One test portion was extracted once, and the resulting 128 extract is pipetted in two wells of a microtiter plate. 129 3.2. Quantitative Methods 130 3.2.1. Bias: Difference between the expectation of the test results and an accepted reference value. Bias 131 is the total systematic error as contrasted to random error. There may be one or more systematic 132 error components contributing to the bias. (3) 133 3.2.2. Calibrant : a material used for calibration of a measurement procedure 134 3.2.3. Limit of detection (LOD): The lowest concentration or mass of analyte in a test sample that can be 135 distinguished from a true blank sample at a specified probability level (ISO 5725-1:1994). See 136 further details on how to determine LOD in Section 5.2.4.3.2. 137 3.2.4. Limit of quantification (LOQ): The lowest level of analyte in a test sample that can be reasonably 138 quantified at a specified level of precision (ISO 5725-1:1994). See further details on how to 139 determine LOQ in Section 5.2.4.3.2. 140