Situation
A laboratory instrument sends calculated moisture results to LIMS through middleware after a firmware and mapping update.
Intended Use
Associate the approved instrument result with the correct sample and method in LIMS without manual transcription.
Decision Summary
| Decision element | Case record |
|---|---|
| GxP assessment | Sample identity, result value, unit, method, approval status, and transfer recovery affect the authoritative laboratory record. |
| Potential impact | The LIMS record can contain a materially incorrect or unauthorized result used for disposition. |
| Known issue | The fictional update sends milligrams per gram while the mapping assumes percent. |
| Validation conclusion | The interface remains disabled until unit mapping is corrected and positive, negative, recovery, and reconciliation tests pass. |
GxP Assessment
Sample identity, result value, unit, method, approval status, and transfer recovery affect the authoritative laboratory record.
Affected GxP Functions
- Sample and method association
- Value and unit mapping
- Approval-state transfer
- Duplicate and order control
- Exception queue and reconciliation
Failure Scenarios
- Result is assigned to the wrong sample
- Unit conversion is incorrect
- Unapproved result posts as final
- Retry duplicates the result
- Failed transfer is not reconciled
Potential Impact
The LIMS record can contain a materially incorrect or unauthorized result used for disposition.
Existing Controls
- Barcode sample identity
- Instrument review
- Middleware acknowledgement
- LIMS status rules
- Daily reconciliation
Existing Evidence
- Instrument qualification
- Supplier firmware release note
- Prior middleware tests
- Approved mapping specification
Evidence Gaps
- Changed field mapping
- Firmware output precision
- Outage recovery
- Duplicate message behavior
Testing Approach
- Script exact value, precision, unit, sample, method, and status mapping
- Challenge missing, invalid, duplicate, delayed, and out-of-order messages
- Test destination outage, retry, and partial transfer
- Reconcile source, middleware, LIMS, and exception records
Deviations or Known Issues
The fictional update sends milligrams per gram while the mapping assumes percent.
Validation Conclusion
The interface remains disabled until unit mapping is corrected and positive, negative, recovery, and reconciliation tests pass.
Reassessment Criteria
- Instrument firmware or method change
- Middleware or schema change
- Unit or precision change
- LIMS workflow change
- Unreconciled result incident