In quality control practice, which term describes adding a known amount of analyte to a sample to assess recovery or QC performance?

• A. Blank sample
• B. Spike
• C. Sample Duplicate
• D. Calibration Curve

Answer: (B)

Spiking is the practice of adding a known amount of analyte to a sample to directly assess recovery and method performance. By introducing a precise quantity and then processing the sample through the usual workflow, you can measure how much of that analyte is recovered at the end. This reveals losses during extraction, cleanup, or detection and helps verify the accuracy and robustness of the QC process. Recovery is typically calculated as (measured amount after processing) divided by (amount added) times 100, giving a percentage that indicates how well the method retains the analyte.

This approach is distinct from using a blank sample, which checks for contamination or background signals; from creating a sample duplicate, which tests precision by repeating measurements on the same material; and from a calibration curve, which establishes the relationship between concentration and signal for quantitation rather than assessing recovery.