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What This Guide Helps With
Troubleshoot repeated clot, air-bubble, or sample-volume errors caused by specimen quality, collection technique, containers, presentation, or sampling-path contamination.
Step-by-Step Troubleshooting
1. Protect Patient Testing and Confirm the Pattern
Do not keep processing patient samples on an analyzer that repeatedly reports sample-integrity or volume problems. Route urgent specimens to another verified analyzer when necessary.
Determine whether the error involves clots, bubbles, insufficient sample, or a combination, and whether it occurs with one specimen or many.
Expected outcome: The specific recurring error pattern is identified and unreliable testing has stopped.
2. Inspect the Specimen
Visually inspect the sample and container for clots, fibrin, excessive air bubbles, leakage, inadequate fill, separation, or other evidence of poor specimen quality.
Follow laboratory specimen-handling requirements and biohazard precautions.
Expected outcome: The specimen is suitable for testing. If a specimen defect explains the error, use an appropriate replacement specimen and troubleshooting can stop if the analyzer then operates normally.
3. Verify Collection Container Condition
Inspect the syringe, capillary, or approved collection device for cracks, loose components, inappropriate caps, damaged tips, or other defects that could introduce air or prevent adequate aspiration.
Expected outcome: The container is intact and suitable for use. If replacing a defective container resolves the issue, verify normal analyzer operation.
4. Confirm Proper Sample Preparation and Presentation
Ensure the sample has been prepared, mixed, and presented according to laboratory procedure. Confirm the container is positioned correctly at the analyzer interface.
Do not attempt to compensate for insufficient volume by forcing or manipulating the sample interface.
Expected outcome: A properly prepared sample is presented correctly and is accepted without error.
5. Compare With Known-Good Control Material
Run appropriate known-good control material or another suitable test sample when permitted.
If the analyzer handles known-good material normally, the problem is more likely associated with specimen collection or preparation rather than the analyzer.
Expected outcome: Known-good material processes without clot, bubble, or volume errors. If so, analyzer troubleshooting can stop after confirming stability.
6. Inspect the Accessible Sample Interface
Check for dried blood, residue, contamination, or visible obstruction at the externally accessible sample inlet. Perform approved cleaning if needed.
Do not insert wires, probes, or other improvised tools into the fluid pathway.
Expected outcome: The accessible sample interface is clean and unobstructed. If errors stop after cleaning, verify with control material.
7. Determine Whether the Error Follows All Samples
If repeated errors occur with multiple known-good samples or controls, document the pattern and stop repeated testing.
This suggests a possible analyzer fluidics, aspiration, volume-detection, or sensing problem.
Expected outcome: Persistent analyzer-related behavior is distinguished from specimen-related errors.
8. Perform Final Functional Verification
After any correction, verify normal aspiration and processing using appropriate control material and complete required QC before returning the analyzer to patient use.
Expected outcome: Samples are processed without repeated clot, bubble, or volume errors and required QC is acceptable.
If the Problem Persists
Specimen integrity, container condition, preparation, positioning, and accessible contamination have been ruled out. Persistent errors may involve the analyzer's internal aspiration pathway, volume sensing, bubble detection, fluidics, or another service-level condition.
The analyzer should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
- Evaluated using appropriate Radiometer documentation and approved test equipment.
- Repaired or configured only by qualified personnel.
Do not attempt internal clot removal, fluid-path disassembly, or sensor adjustment without authorized manufacturer procedures. Complete functional and QC testing before return to service.
Knowing when to stop external troubleshooting and escalate is proper troubleshooting.
Clinical Use Tip
Blood gas specimens are time-sensitive; repeated failed attempts can delay clinically important results, so move promptly to another verified analyzer when the problem is not immediately correctable.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Laboratory staff reported repeated bubble and insufficient-volume errors on the Radiometer ABL90 FLEX PLUS."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the errors occurred only with one damaged sample syringe while known-good control material processed normally."
Resolution
What action was taken.
Example:
"The defective sample container was removed from use, successful processing and QC were verified, and the analyzer remained available for clinical testing."
Helpful Details to Include (If Known)
- Exact clot, bubble, or volume message
- Number of samples affected
- Sample and container type
- Visible clotting or air
- Approximate adequacy of specimen volume
- Container damage or leakage
- Sample-preparation observations
- Known-good control comparison
- Accessible inlet condition
- Cleaning performed
- QC result after correction
- Final device status
Final Thought
Repeated sample-integrity errors should first be separated into specimen, container, presentation, and analyzer causes. Use known-good material to isolate the problem, avoid unnecessary invasive work, and verify acceptable performance before clinical use.
That is successful troubleshooting.