LCS stands for Laboratory Control Samples. What is their primary purpose?

• A. Laboratory Control Samples are prepared and analyzed to assess laboratory performance.
• B. LCS are used to calibrate instruments.
• C. LCS are replaced by matrix spikes.
• D. LCS values are used to determine the sample volume.

Answer: (A)

Quality control in the lab relies on known-reference materials to gauge performance. Laboratory Control Samples are prepared with a known concentration and run through the same procedures as real samples. By comparing the measured value to the known value, you can detect bias, drift, contamination, or other analytical issues and confirm that the method and the lab are producing accurate, reliable data over time. That’s their primary role: to assess overall laboratory performance and data quality.

They aren’t the tools used to calibrate instruments—that job falls to calibration standards used to build a calibration curve. They also aren’t replacements for matrix spikes, which evaluate how the sample matrix affects recovery and accuracy. And they don’t determine how much sample volume to take, which is about pipetting and measurement techniques rather than the performance check provided by LCS.