A calibration drift and the affected product window
A fictional manufacturing line uses a temperature instrument as one input to a defined process record. The instrument is found outside its approved calibration tolerance during a scheduled check. Its last satisfactory check was recorded earlier, but an independent reference channel and maintenance log also exist. Several lots were processed between the two checks. One employee proposes recalibrating the instrument and releasing all lots because the displayed process values were inside the specified range. Another proposes rejecting every lot without examining the independent evidence. The quality team must determine what can be established about the measurement, time window and product impact. The case supplies no actual sterilization recipe, release authorization or universal retrospective correction factor. The task is to plan a defensible investigation while preserving all original records.
1. What needs investigation?
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Preserve the original readings, calibration findings, reference-channel data, maintenance history and lot traceability. Determine the direction and magnitude of error, the relevant period and how measurement error could affect each required process condition.
2. Can recalibration alone release the earlier lots?
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No. Recalibration addresses the instrument future use; earlier product requires an evidence-based impact assessment and authorized disposition. Neither blanket release nor blanket rejection follows solely from the supplied facts.