Guided case: evidence for a potassium bench assessment

A medical laboratory scientist six weeks into independent work on a core chemistry analyzer. The potassium test system uses an ion-selective electrode method. The employee is due for the first-year semiannual competency assessment. The local laboratory policy defines its assessor delegation and critical-value procedure.

During direct observation, the employee verifies specimen identification, centrifugation, analyzer loading, and release for two patient specimens. The assessor reviews documentation that a potassium result of 5.9 mmol/L was flagged high and the required critical-value callback was logged with time, recipient, and read-back confirmation. These observations support routine testing and monitoring, recording, and reporting elements.

The QC log contains two control levels for the prior 30 days. One flag was resolved by a documented recalibration and return to range. At 16:00, a low potassium control of 3.18 mmol/L falls outside the 3.3 to 3.7 mmol/L interval. In the challenge scenario, the employee must state what stops, what records are reviewed, and who is notified before testing resumes.

At the bench, score the employee's response to the failed-control decision separately from the completed routine task.