What steps should be taken when a QC result fails or is out of control?

• A. Ignore the result and continue testing.
• B. Flag the result, repeat the control and patient sample if indicated, investigate root cause, implement corrective action, and report to supervisor as required.
• C. Discard all data and restart the instrument.
• D. Only notify the supervisor after the run has completed.

Answer: (B)

When a QC result is out of control, the priority is to protect patient safety and ensure data integrity by stopping and investigating the issue while keeping proper documentation. The appropriate response is to flag the result in the system, repeat the control and, if indicated, the patient sample to confirm whether the problem lies with the instrument, reagents, or procedure, then perform a root-cause analysis, implement corrective actions, and report to the supervisor as required. This sequence helps verify whether the failure is an isolated event or a systemic problem and ensures that patient results are not released until the QC is back in control. Ignoring the result, discarding data and restarting without investigation, or postponing notification until after the run ends do not address safety, traceability, or accountability and can lead to erroneous results being reported.