What is a Reference Sample?

• A. A quality assurance sample composed of standard reference material used to evaluate laboratory accuracy.
• B. An external QA sample with unknown composition.
• C. A blank sample used for calibration.
• D. A production sample labeled QA.

Answer: (A)

A reference sample is a quality assurance material that contains a standard reference material with a known, traceable value. It’s used to check the accuracy of laboratory measurements by providing a stable benchmark against which results can be compared. Running such a sample alongside routine tests helps identify bias, drift, or method issues and confirms that the instrument and method are producing correct values over time.

This is distinct from other options: an external QA sample with unknown composition won’t give a definite target value to verify accuracy; a blank sample is used to assess background or zero resistance but doesn’t provide a known concentration to verify measurement accuracy; and a production sample labeled QA is intended for process control rather than validating measurement accuracy against a standard reference.