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What This Guide Helps With
Troubleshoots out-of-range QC by separating control-material, reagent, calibration, handling, environmental, and analyzer-performance causes before service escalation.
Step-by-Step Troubleshooting
1. Protect Patient Results and Confirm the QC Failure
Do not release affected patient results contrary to laboratory policy when QC is unacceptable.
Confirm:
- Assay involved
- QC level involved
- Whether one or multiple levels fail
- Whether the failure is new or recurring
- Whether multiple assays are affected
- The direction and pattern of the QC shift
Clinical Engineering should preserve the distinction between analyzer troubleshooting and the laboratory's clinical interpretation of QC.
Expected outcome: Affected testing is identified and appropriately held while the failure is investigated.
2. Confirm Analyzer Status
Check for active analyzer faults involving:
- Reagent recognition
- Calibration
- Pipetting
- Aspiration
- Fluidics
- Wash systems
- Temperature
- Consumables
Resolve any legitimate analyzer readiness fault before interpreting repeated QC attempts.
Expected outcome: No unresolved analyzer alarm explains the QC failure.
3. Have Laboratory Staff Verify QC Material
Authorized laboratory personnel should confirm:
- Correct QC material
- Correct level
- Proper preparation
- Appropriate storage and handling
- Correct identification
- Sufficient volume
- No obvious contamination
Do not independently override laboratory QC handling requirements.
Expected outcome: QC material handling is verified before analyzer failure is suspected.
4. Verify Reagent and Calibration Status
Confirm the affected assay's reagent is recognized and that required calibration status is acceptable.
Look for recent:
- Reagent replacement
- Lot change
- Calibration
- Maintenance
- Extended analyzer downtime
Document these factors for laboratory review.
Expected outcome: Reagent and calibration conditions are known and consistent with normal testing.
5. Check Sample Presentation and Aspiration Conditions
Inspect the QC tube and carrier for:
- Correct seating
- Adequate accessible volume
- Bubbles or foam
- Obvious clot or debris
- Damaged carrier
- Improper placement
Expected outcome: QC material can be aspirated normally without an obvious physical sampling problem.
6. Repeat QC Only After Appropriate Review
If laboratory policy supports repeating QC, use freshly prepared or verified QC material when appropriate and avoid repeated reruns without investigating the underlying cause.
Compare whether the result:
- Returns to acceptable range
- Remains consistently shifted
- Varies widely between repeats
Expected outcome: A handling-related or transient issue is either corrected or ruled out.
7. Determine Whether the Pattern Is Assay-Specific
Compare unaffected assays and other QC levels.
A single-assay problem may involve assay-specific:
- Reagent
- Calibration
- Control material
Broad QC shifts may suggest:
- Pipetting
- Fluidics
- Temperature
- Wash performance
- Environmental conditions
- Common analyzer functions
Expected outcome: The scope of the QC issue is defined without claiming a failed internal component.
8. Inspect External Environmental and Supply Conditions
Verify:
- Normal analyzer operating environment
- No obvious temperature excursion in the room
- No active leakage
- Adequate wash or system fluid supply
- Waste handling is normal
- No recent facility event affecting the analyzer
Expected outcome: No external environmental or supply condition explains the abnormal QC.
9. Perform Final Verification
When the identified cause has been corrected:
- Confirm analyzer readiness
- Have laboratory staff repeat required QC
- Confirm results meet laboratory acceptance criteria
- Verify no unresolved analyzer faults remain
Expected outcome: Required QC is acceptable and the laboratory authorizes return to patient testing. Troubleshooting is complete.
10. Escalate Persistent QC Failure
If QC remains unacceptable after verified controls, reagent status, calibration, sample presentation, supplies, and environment are checked, stop external troubleshooting.
Expected outcome: Affected testing remains suspended and the analyzer is escalated for qualified evaluation.
If the Problem Persists
External and laboratory-process causes have been reviewed. Persistent QC failure may involve pipetting accuracy, fluidics, optical or measurement systems, temperature regulation, wash performance, calibration/configuration, or another service-level condition.
The affected analyzer or module should be:
- Removed from service as required by laboratory policy
- Labeled Out of Service when appropriate
- Sent for repair or qualified service evaluation
- Evaluated using Roche-approved documentation and approved test equipment
- Repaired, calibrated, or configured only by qualified personnel
Required calibration and QC must be successfully completed before patient testing resumes.
Knowing when to stop external troubleshooting and escalate is proper troubleshooting.
Clinical Use Tip
Treat abnormal QC as a result-integrity problem, not merely an analyzer alarm; patient results remain dependent on laboratory QC acceptance.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Laboratory staff reported QC for one chemistry assay shifted out of the laboratory's acceptable range."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering and laboratory staff found the QC tube contained visible bubbles that interfered with consistent aspiration."
Resolution
What action was taken.
Example:
"Laboratory staff prepared a verified replacement QC sample, Clinical Engineering confirmed normal aspiration, and repeat QC met laboratory acceptance criteria."
Helpful Details to Include (If Known)
- Assay and QC level affected
- Direction or pattern of QC shift
- Number of failed QC runs
- Reagent and calibration status
- Recent lot or reagent change
- QC tube condition
- Bubble, foam, clot, or volume observations
- Other assays affected
- Active analyzer alarms
- Environmental or supply conditions
- QC result after correction
- Final testing status
Final Thought
Out-of-range QC requires protection of result integrity first. Verify control material, reagent, calibration, sampling, and external conditions before assuming internal failure, and return testing only after laboratory acceptance.
That is successful troubleshooting.