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What This Guide Helps With
Troubleshooting sample aspiration, clot detection, liquid level sensing, short sample, probe blockage, or sample handling errors before repair escalation.
Step-by-Step Troubleshooting
Ensure Patient Safety and Result Integrity First
Confirm whether any patient samples were affected by the aspiration, clot, or liquid level sensing error.
Do not release questionable results until the affected specimen and analyzer status have been reviewed by laboratory staff.
Expected outcome: Patient results are protected from possible sampling or volume-related error.
Confirm the Exact Error or Symptom
Review the Dimension EXL 200 error message, event log, or operator report.
Determine whether the issue involves:
- Sample probe aspiration failure
- Clot detection alarm
- Liquid level sensing error
- Short sample or insufficient sample volume
- Repeated errors on one tube
- Repeated errors across multiple tubes
- Probe crash, obstruction, or abnormal movement
- Error occurring during calibration, QC, or patient testing
Expected outcome: The problem is separated into a sample-specific issue, probe issue, or broader analyzer problem.
Check Whether the Error Follows One Specimen
Ask the lab whether the same sample failed repeatedly or if many samples are failing.
Inspect the affected tube for low volume, foam, bubbles, fibrin, clots, gel interference, improper tube type, or poor sample separation.
Expected outcome: If the problem follows one tube, the issue is likely specimen-related. Have the lab recollect, centrifuge, aliquot, or process the sample per lab policy.
Verify Sample Tube Placement and Rack Loading
Confirm the tube is fully seated in the rack and positioned correctly for the analyzer.
Check that the rack is appropriate, not damaged, and loaded in the correct orientation.
Expected outcome: The analyzer can reliably locate the sample tube and access the specimen.
Check Sample Volume and Cup Compatibility
Confirm the sample volume is above the minimum required level for the ordered testing and container type.
If sample cups or pediatric cups are used, verify they are seated correctly and are compatible with the analyzer setup.
Expected outcome: The probe reaches liquid properly without triggering a false low-volume or liquid level error.
Inspect for Foam, Bubbles, or Surface Film
Ask the lab to visually inspect the sample surface. Foam, bubbles, or film can interfere with liquid level sensing and aspiration.
Expected outcome: If foam or bubbles are present, the sample should be corrected or replaced according to lab procedure before retesting.
Check for Clots, Fibrin, or Poor Separation
Have lab staff inspect the specimen for clots, fibrin strands, gel disturbance, or inadequate centrifugation.
Do not manually manipulate specimens unless permitted by laboratory policy.
Expected outcome: A specimen integrity issue is identified or ruled out before assuming analyzer failure.
Inspect the Sample Probe Externally
With the analyzer in a safe stopped or maintenance state, visually inspect the sample probe area.
Look for obvious bending, dried residue, salt buildup, misalignment, sample splash, or obstruction around the probe path.
Expected outcome: The probe appears clean, straight, and unobstructed. If the probe is bent or damaged, stop troubleshooting and escalate.
Check for Probe Contact or Collision Evidence
Ask whether there was a recent sample tube misload, rack jam, probe strike, or sudden increase in sampling errors.
A probe that contacted a tube, cap, rack, or obstruction may no longer aspirate or sense liquid correctly.
Expected outcome: Recent mechanical contact is identified as a possible cause and the unit is not returned to service without evaluation.
Confirm Covers, Doors, and Interlocks Are Properly Closed
Verify all relevant covers, sample area doors, and access panels are fully closed.
Some analyzer functions may stop, inhibit, or alarm if access covers are not properly secured.
Expected outcome: The analyzer is in a valid operating state before additional troubleshooting.
Check Reagent, Diluent, Wash, and Waste Status
Review the analyzer status for low fluids, empty containers, full waste, or fluidics-related alarms that could affect sampling.
Expected outcome: Supporting fluids and waste paths are available, and the sample error is not secondary to a broader fluidics problem.
Review Recent Maintenance or Cleaning Activity
Ask whether probe cleaning, consumable replacement, daily maintenance, or service activity occurred shortly before the error began.
Confirm no caps, tubing, containers, racks, or accessories were left out of position.
Expected outcome: A recent maintenance-related setup issue is identified or ruled out.
Run the Appropriate Operator-Level Probe Cleaning or Prime Routine
Coordinate with the lab to run approved maintenance routines for sample probe cleaning, wash, or fluidics priming if available to Clinical Engineering at the site.
Avoid internal disassembly or service-level calibration unless authorized and trained.
Expected outcome: Minor residue, air, or external fluid path interruption is cleared. If the error resolves, document the action and stop.
Test With a Known-Good Sample or Control Material
Have the lab repeat testing using an acceptable known-good specimen, control, or sample container appropriate for their workflow.
Expected outcome: If the known-good sample runs correctly, the original sample or container was likely the cause.
Determine Whether the Issue Is Intermittent or Repeatable
If the error repeats, note whether it occurs with all samples, one rack position, one container type, one assay, or after a specific number of tests.
Expected outcome: A repeatable pattern is captured for service escalation.
Do Not Continue Testing if Sampling Reliability Is Uncertain
If the analyzer continues to produce aspiration, clot detection, or liquid level sensing errors after external checks, remove it from clinical use for affected testing.
Expected outcome: The analyzer is not used for patient testing until sample handling reliability is verified.
If the Problem Persists
If the sample tube, sample volume, rack loading, specimen condition, external probe condition, fluids, waste, covers, and basic maintenance routines have been checked and the issue remains, common external causes have been ruled out.
The problem may involve an internal sample probe assembly, liquid level sensing circuit, clot detection function, aspiration path, pressure/vacuum control, valve, pump, alignment, or analyzer control issue.
The device should be:
- Removed from service for affected testing
- Labeled Out of Service
- Sent for repair, vendor service, or bench evaluation according to site policy
Knowing when to stop is proper troubleshooting. Continuing to run patient samples on a chemistry analyzer with unresolved sampling errors can create result integrity risk.
Clinical Use Tip
Do not troubleshoot sample aspiration or liquid level errors while the analyzer is actively processing patient samples unless the system is already stopped and the lab confirms it is safe. Coordinate with laboratory leadership before pausing testing, removing samples, or returning the Dimension EXL 200 to service.
If testing must continue, move patient testing to a backup analyzer or approved alternate workflow first so therapy continuity and result integrity are protected.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Laboratory reported repeated sample probe aspiration and liquid level sensing errors on the Siemens Dimension EXL 200 during patient sample processing."
Cause
What was observed during troubleshooting.
Example:
"External troubleshooting found low-volume and foamy specimens in the affected rack; no visible probe damage or fluid supply issue was observed."
Resolution
What action was taken.
Example:
"Affected specimens were removed for laboratory review, rack loading and sample volume were verified, probe area was visually inspected, and analyzer operation was confirmed with an acceptable known-good sample before return to service."
Helpful Details to Include (If Known)
- Exact error code or message
- Whether issue affected one sample or multiple samples
- Sample tube type and rack position
- Sample volume verified
- Foam, bubbles, clot, fibrin, or gel interference observed
- Probe condition checked
- Rack and tube seating checked
- Fluid and waste status reviewed
- Maintenance or cleaning routine performed
- Whether controls or known-good samples passed
- Final analyzer status
Final Thought
Sample aspiration and liquid level sensing issues should be handled carefully because they directly affect specimen integrity and patient results. Start with the sample, rack, tube, volume, and visible probe condition before suspecting internal failure. If basic checks do not restore reliable sampling, remove the analyzer from service and document the complaint, cause, and resolution clearly.
That is successful troubleshooting.