- Assay anomaly (hypothetical run)
  - [Q] Why did the treated samples produce a weaker signal?
    - [C] The detection reagent degraded before the run.
      - [linked] Weak controls implicate the reagent only if they shared its lot.
        - [G] Positive controls were also weaker than their historical range.
        - [G] The controls used the same reagent lot as the treated samples.
          - [?] Confirm the lot numbers on the run sheet.
      - [G] The reagent was left at room temperature overnight.
      - [O] The low readings may instead be a plate-position effect.
        - [G] Most low readings occurred along the outer wells.
    - [?] Repeat with a fresh reagent and randomized well positions.