AOAC Guidance on FA Immunoassay Validation (November 2023)

3.2.4. Limit of quantification (LOQ): The lowest level of analyte in a test sample that can be reasonably 139 quantified at a specified level of precision (ISO 5725-1:1994). See further details on how to 140 determine LOQ in Section 5.2.4.3.2. 141 3.2.5. LOQ RSD : A limit of quantification with a specified relative standard deviation, expressed as a 142 percentage. For example, an LOQ 10 from a single laboratory validation would be the concentration 143 where the RSD i = 10%. In the case of an LOQ RSD estimated from a collaborative study, an LOQ 30 would 144 be the concentration where the RSD R = 30%. 145 3.2.6. Measurement range: the concentration range over which the target analyte can be reliably 146 quantified/detected 147 3.2.7. Recovery: The fraction or percentage of analyte that is recovered when the test sample is 148 analyzed using the entire method 149 3.2.8. Precision: Closeness of agreement between independent test/measurement results obtained 150 under stipulated conditions. (ISO 3534-2:2006) 151 3.2.9. Repeatability: Precision under repeatability conditions. (ISO 3534-2:2006). (Repeatability 152 Conditions: Observation conditions where independent test results are obtained with the same 153 method on equivalent test items in the same laboratory by the same operator using the same 154 equipment within short intervals of time. (ISO 3534-2:2006, with minor modifications) 155 3.2.10. Reproducibility: Precision under reproducibility conditions (ISO 3534-2:2006). (Reproducibility 156 Conditions: Observation conditions where independent test results are obtained with the same 157 methods on equivalent test items in different laboratories with different operators using different 158 equipment. (ISO 3534-2:2006, with minor modifications)) 159 3.2.11. Intermediate precision: precision under intermediate conditions (ISO 3534-2). (Intermediate 160 precision conditions: conditions where test results or measurement results are obtained with the 161 same method, on identical test/measurement items in the same test or measurement facility, 162 under some different operating condition.) 163 3.2.11.1. Note 1 to entry: There are four elements to the operating condition: time, calibration, 164 operator and equipment. 165 3.2.11.2. The specific and minimum conditions applicable for validation of food allergen 166 immunoassays are described in section 5.2.4.2.2 167 3.2.11.3. For the purposes of this document, the subscript notation "i" will be used to indicate terms 168 and estimators associated with intermediate precision. Estimation methods can be found in 169 section 5.2.4.2.3. 170 3.3. Qualitative Methods 171 3.3.1. Probability of detection (POD) : The proportion of positive analytical outcomes for a qualitative 172 method for a given matrix at a given analyte level or concentration. POD is concentration 173 dependent. 174 3.3.2. Claimed Detection Capability (CDC): An analyte concentration that demonstrates a POD of at least 175 0.90, with 95% confidence. This may be estimated across all matrices, or individually per matrix. 176 The claimed detection capability must be verified empirically during method validation. 177 3.3.3. Fractional recovery: Validation criterion that is satisfied when an unknown sample yields both 178 positive and negative responses within a set of replicate analyses. (5) 179