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What This Guide Helps With
Troubleshoots repeated clot, bubble, or volume errors caused by specimen quality, collection, handling, positioning, aspiration conditions, or external loading problems.
Step-by-Step Troubleshooting
1. Protect Patient Testing and Confirm the Pattern
Do not report results from specimens repeatedly flagged for clot, bubble, or volume problems until specimen integrity and analyzer performance are verified.
Determine whether the problem affects:
- One specimen
- Several specimens from one collection area
- One rack or position
- Multiple unrelated specimens
- All testing
Record the exact analyzer message.
Expected outcome: The problem is identified as specimen-specific, workflow-related, or analyzer-wide.
2. Inspect the Specimen
Visually inspect according to laboratory procedure for:
- Clot or fibrin
- Visible bubbles
- Foam
- Insufficient volume
- Grossly abnormal filling
- Damaged tube
- Leakage or contamination
Do not manipulate a compromised patient specimen solely to make the analyzer accept it.
Expected outcome: Specimen suitability is established. If the specimen is clearly unsuitable, obtain or process an appropriate replacement according to laboratory policy.
3. Verify Collection and Handling Information
When repeated specimen-quality errors occur, confirm with laboratory staff whether:
- Collection technique was appropriate
- Tubes were filled appropriately
- Specimens were mixed or handled according to laboratory procedure
- Transport or delay may have affected the sample
Clinical Engineering should not redefine laboratory specimen-acceptance criteria.
Expected outcome: No obvious pre-analytical handling problem remains unexplained.
4. Verify Sample Position and Container
Confirm the specimen is:
- In the appropriate container for the workflow
- Correctly seated
- Adequately accessible to the aspiration system
- Not obstructed by the cap, label, or rack
Expected outcome: The analyzer can access the sample correctly.
5. Compare with a Known-Good Specimen or QC Material
Use appropriate known-good material according to laboratory policy.
If the known-good material processes normally while the affected sample does not, the problem is likely specimen-specific.
If multiple verified materials fail similarly, investigate the analyzer.
Expected outcome: The issue is isolated to the specimen or the analyzer.
6. Check for Related Aspiration or Fluidics Errors
Review whether the analyzer is also showing:
- Probe errors
- Aspiration errors
- Wash faults
- Waste faults
- Fluidics alarms
- Irregular sample detection
These may indicate that a sample-quality message is secondary to a broader liquid-handling problem.
Expected outcome: No broader analyzer condition is present.
7. Inspect Accessible Loading and Aspiration Areas
Check externally accessible areas for:
- Dried specimen material
- Debris
- Broken tube fragments
- Obvious obstruction
- Visible contamination
Clean only using approved procedures.
Expected outcome: No external obstruction contributes to repeated sample errors.
8. Perform Final Verification
After an external or specimen-related cause is corrected, process suitable verification material and required QC.
Expected outcome: Sample handling occurs without repeat clot, bubble, or volume errors and required QC is acceptable. Troubleshooting can stop.
If the Problem Persists
If multiple appropriate specimens or QC materials produce repeated clot, bubble, or volume errors despite correct positioning and external conditions, common specimen-related causes have been ruled out.
The remaining cause may involve liquid-level sensing, aspiration pressure or vacuum, probe operation, fluidics, sample detection, or another service-level subsystem.
The analyzer should be:
- Removed from service if specimen handling cannot be trusted
- 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 bypass sample-quality detection or force acceptance of questionable specimens.
Return the analyzer to service only after reliable specimen handling and required QC are demonstrated.
Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Repeated clot or volume errors across multiple patient samples may indicate a broader analyzer problem and should not automatically be blamed on collection technique.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Laboratory staff reported repeated low-volume errors for one patient specimen on the ACL TOP 750 LAS."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the affected specimen did not contain enough accessible sample volume for reliable aspiration."
Resolution
What action was taken.
Example:
"Laboratory staff provided an acceptable replacement specimen, Clinical Engineering verified normal processing without repeat error, and QC remained acceptable."
Helpful Details to Include (If Known)
- Exact analyzer message
- Number of specimens affected
- Collection area or workflow
- Tube type and condition
- Visible clot, fibrin, bubbles, or foam
- Approximate sample availability
- Rack and position
- Known-good material result
- Related aspiration or fluidics alarms
- QC result
- Final analyzer status
Final Thought
Separate specimen-quality problems from analyzer problems using careful inspection and known-good comparisons, and escalate when repeated errors occur with verified material.
That is successful troubleshooting.