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What This Guide Helps With
Sample aspiration problems caused by inadequate specimen volume, presentation, collection devices, clots, leaks, contamination, or sample-path obstruction.
Step-by-Step Troubleshooting
1. Protect Patient Testing and Preserve the Specimen
Do not rely on repeated aspiration attempts when a patient result is urgently needed. Redirect testing to another verified analyzer if necessary and preserve or recollect the specimen according to clinical policy.
Avoid excessive manipulation of a specimen that could affect result integrity.
Expected outcome: Patient testing continues safely and the analyzer can be evaluated without delaying clinical care.
2. Confirm the Exact Aspiration Problem
Determine whether the analyzer does not begin aspiration, starts but stops early, reports insufficient sample, aspirates air, or fails only with a particular collection device.
Record any displayed message before clearing it.
Expected outcome: The aspiration failure is clearly characterized and reproducible conditions are identified.
If the device aspirates an appropriate sample normally during observation, verify operation and troubleshooting can stop.
3. Inspect the Sample and Collection Device
Confirm the specimen has sufficient accessible volume for the intended test and is presented in an appropriate compatible collection device.
Inspect for visible bubbles, clotting, separation, leakage, damaged syringes or capillary devices, loose connections, or obstructions at the sample opening.
Expected outcome: The specimen and collection device are suitable for presentation to the analyzer.
If replacing a damaged or unsuitable collection device resolves aspiration and a valid test can be completed, troubleshooting can stop.
4. Verify Proper Sample Presentation
Observe how the specimen is being presented to the analyzer. Confirm the sample container is positioned and connected as intended and that the sample inlet can access liquid rather than air.
Do not force sample devices onto the inlet.
Expected outcome: The specimen is positioned so the analyzer can aspirate it without drawing air or losing contact with the sample.
If correct presentation restores normal aspiration, verify successful processing and troubleshooting can stop.
5. Inspect the Accessible Sample Inlet
With the analyzer not processing a patient specimen, inspect the accessible sample inlet area for dried blood, debris, contamination, or obvious obstruction.
Use only cleaning methods and materials authorized for the device. Do not probe internal tubing or fluid paths with improvised tools.
Expected outcome: The accessible sample inlet is clean and unobstructed.
If safe external cleaning resolves aspiration, complete functional verification before returning the analyzer to use.
6. Test With an Appropriate Known-Good Sample Device or Approved Test Material
When permitted by facility procedure, compare operation using an appropriate known-good collection device or approved material intended for analyzer verification.
This helps distinguish a specimen or collection-device problem from an analyzer-side aspiration problem.
Expected outcome: The analyzer aspirates the known-good test setup normally or reproduces the same failure.
If the analyzer functions normally with the comparison setup, address the original specimen or collection-device issue and troubleshooting can stop after verification.
7. Check for Related Clot or Obstruction Indications
Review current analyzer status for any clot, obstruction, fluid-path, or cartridge-related messages associated with the aspiration failure.
Do not attempt internal clearing procedures unless specifically authorized for Clinical Engineering under approved service documentation.
Expected outcome: No unresolved analyzer condition remains that explains the aspiration problem.
If an externally correctable condition is identified and normal aspiration returns, verify operation and stop.
8. Perform Final Functional Verification
Complete an appropriate analyzer verification using approved materials and ensure sample uptake is smooth, processing completes, and no insufficient-sample or aspiration condition recurs.
Follow required quality-control processes before clinical use.
Expected outcome: The analyzer consistently aspirates appropriate samples and completes testing without recurrence.
If achieved, troubleshooting is complete.
9. Escalate Persistent Aspiration Failure
If aspiration continues to fail with suitable samples and collection devices after external inspection and verification, remove the analyzer from clinical use.
Do not disassemble pumps, valves, tubing, sensors, or cartridge interfaces without approved service authorization.
Expected outcome: A persistent internal fluid-handling or sensing problem is referred for qualified evaluation.
If the Problem Persists
External sample volume, sample presentation, collection-device, inlet cleanliness, and obvious obstruction causes have been ruled out. The remaining problem may involve the internal aspiration pathway, pressure or flow sensing, cartridge fluidics, mechanical components, or software control.
The analyzer should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate Werfen documentation and approved test equipment
- Repaired or configured only by qualified personnel
Complete required analyzer checks, quality-control verification, and return-to-service testing after repair.
Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Do not repeatedly aspirate a compromised patient specimen; unnecessary handling can affect sample integrity and delay clinically important blood gas results.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported repeated insufficient-sample messages and failure to aspirate specimens on the GEM Premier 7000."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found dried material around the accessible sample inlet that interfered with proper sample presentation."
Resolution
What action was taken.
Example:
"Cleaned the accessible inlet using the approved method, verified normal aspiration with appropriate test material, completed required checks, and returned the analyzer to service."
Helpful Details to Include (If Known)
- Exact aspiration or insufficient-sample message
- Collection device used
- Visible sample volume
- Presence of bubbles or clots
- Sample inlet condition
- Whether multiple specimens were affected
- Known-good comparison results
- Cartridge status
- Results of approved verification testing
- Final analyzer status
Final Thought
Protect the patient testing pathway first, then evaluate the specimen, collection device, presentation, inlet, and related analyzer conditions before suspecting internal fluidics. Verify normal aspiration before return to service and escalate persistent failures appropriately.
That is successful troubleshooting.