What is the primary purpose of control materials in QC?

What is the primary purpose of control materials in QC?

• A. To monitor accuracy and precision and detect drift.
• B. To calibrate instruments at startup only.
• C. To extend reagent shelf life.
• D. To measure sample volume.

Answer: (A)

Control materials are used to verify that the testing process is performing correctly by providing a sample with a known value that goes through the same analytical steps as patient samples. By repeatedly measuring these controls, you can assess both accuracy (how close results are to the true value) and precision (how reproducible results are across runs). When control results wander beyond predefined limits or show a trend over time, it signals potential biases, imprecision, or drifting performance in the method, instrument, or reagents, prompting investigation before patient results are affected. This is why control materials are used throughout testing and tracked on control charts to detect both gradual drift and sudden shifts. They’re not merely for initial calibration, nor do they extend reagent shelf life or measure sample volume.

Control materials are used to verify that the testing process is performing correctly by providing a sample with a known value that goes through the same analytical steps as patient samples. By repeatedly measuring these controls, you can assess both accuracy (how close results are to the true value) and precision (how reproducible results are across runs). When control results wander beyond predefined limits or show a trend over time, it signals potential biases, imprecision, or drifting performance in the method, instrument, or reagents, prompting investigation before patient results are affected. This is why control materials are used throughout testing and tracked on control charts to detect both gradual drift and sudden shifts. They’re not merely for initial calibration, nor do they extend reagent shelf life or measure sample volume.