AOAC Guidance on FA Immunoassay Validation (August 2023)

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6.2.2.3. Interference

6.2.2.3.1. Study Design

6.2.2.3.1.1. One test portion of each food material in the cross-reactivity panel should be spiked with food allergen material at a concentration expected to yield > 95% POD, with a maximum concentration of 3x CDC, to evaluate interference.

6.2.2.3.2. Data Analysis and Reporting

6.2.2.3.2.1. All results must be reported. If any analysis is repeated, both datasets must be

reported and a justification given for all repeat analysis.

6.2.2.3.3. Acceptance Criteria

6.2.2.3.3.1. Results of the spiked sample analysis are acceptable and not indicative of interference if all spiked samples deliver results of positive (detected). 6.2.2.3.3.2. In the event that a positive spiked sample delivers a result of not detected, it may be re-tested in 20 replicates, with no additional failures allowed, to rule

out interference.

6.2.2.3.3.3. Interference reporting: If interference is observed, corresponding information must be included in the applicability statement of the kit insert, validation

report, and validation certificate.

6.2.3. Matrix Study

6.2.3.1. Scope : The matrix study is a single-laboratory study designed to demonstrate that a candidate method can detect the target compound in the claimed matrixes or

environmental samples, at the claimed detection capability (CDC).

6.2.3.2. Test Materials

6.2.3.2.1. For studies claiming applicability to finished product or ingredient analysis, incurred

matrices are required. See Annex A for preparation guidelines.

6.2.3.2.2. For studies claiming applicability to environmental surface samples, see Annex B for target compound spike preparation guidelines and approved food contact material surfaces that should be considered environmental matrices. Applicability

statements will be specific to the types of surfaces analyzed.

6.2.3.3. Study Design

6.2.3.3.1. POD (0) Validation

6.2.3.3.1.1. For each matrix, a sufficient number of blank test portions must be analyzed to demonstrate with 95% confidence, that the POD(0) is less than 0.1. 6.2.3.3.1.2. For example, 40 blank test matrix portions may be tested, with 40/40

delivering a result of not detected (negative).

6.2.3.3.1.3. Additional possible numbers of test portions to achieve the appropriate

confidence level can be found in Table A7 of Appendix F. (3)

6.2.3.3.2. Probability of Detection (POD) Study

6.2.3.3.2.1. The objective of the POD study is to estimate the concentrations at which the method will deliver full, fractional, or no detection of the target analyte in the