When should controls be used in a laboratory to ensure accuracy?

Using controls each time an assay is performed is essential for ensuring the accuracy and reliability of laboratory results. Quality control (QC) procedures help detect any systematic errors that may arise during testing. This consistent use of controls allows laboratories to monitor variations in measurement that could occur due to factors such as calibration drift, changes in reagent performance, or operator technique.

By analyzing control samples that have known concentrations, laboratories can confirm that the analytical method is functioning correctly. If the results of the controls fall within an acceptable range, it indicates that the assay is performing as expected. Conversely, if the control results are outside the expected range, it may signal an issue that needs to be addressed, ensuring that patient results reported from the assay are valid and accurate.

In contrast, using controls only for new protocols or at the beginning of an analytical run does not provide continuous assurance of assay performance, and checking them solely when troubleshooting equipment limits their effectiveness in error detection.