The acceptance criteria for QC samples are usually defined in the method validation protocol. Common criteria include:
Accuracy: The percentage deviation of the measured concentration from the nominal concentration should be within a specified range (e.g., ±15%). Precision: The coefficient of variation (CV) of replicate measurements should be within a specified range (e.g., ≤15%). Stability: QC samples should remain stable under the storage and analytical conditions used in the study.