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What This Guide Helps With
Troubleshoots probe, pipetting, and aspiration errors caused by sample condition, positioning, obstruction, consumables, fluid supply, or accessible contamination.
Step-by-Step Troubleshooting
1. Protect Patient Testing and Confirm the Error
Do not rely on results from a sample that may not have been aspirated or dispensed correctly.
Identify whether the problem affects:
- One specimen
- One reagent
- One loading position
- Multiple samples
- All aspiration attempts
Record the exact analyzer message and where in the workflow the error occurs.
Expected outcome: The aspiration or pipetting failure is clearly defined and potentially affected results are contained.
2. Inspect the Sample or Reagent
Check the affected container for:
- Insufficient volume
- Clot or fibrin
- Visible bubbles
- Foam
- Improper container
- Mispositioning
- External contamination
Do not attempt to force processing of a visibly compromised specimen.
Expected outcome: The material presented for aspiration is suitable for testing.
3. Verify Container Positioning
Confirm the tube, cup, reagent, rack, or carrier is fully seated and correctly oriented.
Check that labels, caps, or adjacent containers do not interfere with access.
Expected outcome: The aspiration target is correctly positioned. If repositioning restores normal operation, troubleshooting can stop after successful repeat testing with appropriate material.
4. Inspect Accessible Probe Areas
With the analyzer in the appropriate safe condition, inspect externally accessible areas around the probe or aspiration pathway for:
- Dried material
- Visible contamination
- Foreign objects
- Obstruction
- Physical damage visible without disassembly
Do not bend, straighten, reposition, or manually move a probe unless specifically authorized by current service procedures.
Expected outcome: No external obstruction is present.
5. Check Associated Consumables and Fluid Supplies
Verify any accessible consumables required for normal aspiration or cleaning are:
- Present
- Correctly installed
- Not empty
- Not visibly kinked or disconnected where externally accessible
Also check for concurrent wash, waste, or fluidics warnings.
Expected outcome: Required external consumables and fluid pathways appear available and properly connected.
6. Test with Known-Good Material
If appropriate and consistent with laboratory procedures, test a known-good sample container or reagent setup.
Determine whether the error follows:
- A specific sample
- A specific rack
- A specific reagent
- All aspiration events
Expected outcome: The problem is isolated to the material or remains analyzer-related.
7. Observe a Normal Processing Cycle
After correcting an external issue, observe a normal sample or QC cycle.
Confirm:
- No repeat aspiration alarm
- Normal sample access
- No abnormal probe motion
- No unusual sound
- Normal completion of the test cycle
Expected outcome: Aspiration and pipetting complete without error. Troubleshooting can stop after required QC or verification testing.
8. Perform Final Verification
Run appropriate laboratory verification or QC before returning affected assays to patient use.
Expected outcome: The analyzer demonstrates reliable sample handling and required QC is acceptable.
If the Problem Persists
If sample condition, volume, container position, consumables, accessible probe areas, and external fluid supplies have been verified but aspiration errors continue, common external causes have been ruled out.
The remaining cause may involve the pipetting mechanism, probe alignment, liquid-level sensing, pressure or vacuum control, tubing, valves, pumps, motion systems, or other service-level components.
The analyzer should be:
- Removed from service if aspiration reliability cannot be assured
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using current Werfen documentation and approved test equipment
- Repaired or adjusted only by qualified personnel
Do not disassemble probe assemblies, adjust internal mechanisms, or bypass sensing systems without authorized procedures.
Return the analyzer to service only after reliable aspiration and required QC have been demonstrated.
Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
A sample that was not aspirated correctly may produce an unreliable result even if the analyzer completes part of the test cycle.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Laboratory staff reported repeated aspiration errors while testing samples on the ACL TOP 750 LAS."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found one affected sample tube contained visible fibrin that interfered with aspiration."
Resolution
What action was taken.
Example:
"The compromised specimen was removed from testing, a suitable replacement specimen was processed without error, and analyzer QC remained acceptable."
Helpful Details to Include (If Known)
- Exact aspiration or probe message
- Sample, reagent, or rack involved
- Sample volume
- Visible clot, fibrin, bubbles, or foam
- Container position
- Probe-area contamination
- Wash or fluidics alarms
- Known-good comparison results
- Results after correction
- QC result
- Final analyzer status
Final Thought
Protect result accuracy by checking the sample, positioning, consumables, and accessible aspiration path before assuming an internal pipetting fault, and escalate when reliable liquid handling cannot be demonstrated.
That is successful troubleshooting.