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What This Guide Helps With
Use this guide for unstable or unacceptable dialysate conductivity caused by concentrate supply, connections, preparation, water supply, setup, or service-level faults.
Step-by-Step Troubleshooting
1. Protect the Patient and Stop Unreliable Dialysate Delivery
Do not continue treatment when dialysate conductivity cannot be verified as acceptable. If the condition occurs during treatment, follow the clinical procedure for maintaining patient safety and transfer to another verified machine when required.
Do not bypass conductivity monitoring or defeat protective alarms.
Expected outcome: The patient is no longer dependent on a machine with questionable dialysate composition. Troubleshooting can proceed safely.
2. Confirm the Reported Condition
Determine whether conductivity fails to stabilize during preparation, changes intermittently, remains consistently high or low, or becomes abnormal only after treatment begins.
Record the displayed condition and any associated messages before changing the setup.
Expected outcome: The exact pattern is documented and distinguished from a one-time setup error.
3. Verify the Correct Concentrates Are Present
Confirm the prescribed and facility-approved concentrate products are being used and that containers are correctly identified, adequately filled, and not visibly contaminated or damaged.
Check that acid and bicarbonate sources have not been swapped, mixed incorrectly, or connected to the wrong pickup path.
Expected outcome: Correct concentrate sources are available and properly identified. If an incorrect concentrate setup is found and correcting it restores stable conductivity, proceed to final verification and stop troubleshooting.
4. Inspect Concentrate Connections
Inspect accessible concentrate connectors, pickup tubes, caps, hoses, and interfaces for looseness, kinks, cracks, blocked openings, air entry, or incomplete insertion.
Reseat accessible connections as appropriate without opening internal fluid pathways.
Expected outcome: Concentrate connections are secure and capable of supplying fluid without visible restriction or air entry.
5. Check Concentrate Supply and Pickup
Confirm pickup tubing is actually immersed in the intended solution and is not resting above the fluid level, pressed against a container wall, kinked, or drawing visible air.
If allowed by facility practice, replace a questionable concentrate container with a verified known-good container of the correct product.
Expected outcome: The machine has a continuous external concentrate supply. If conductivity stabilizes after correcting the supply, troubleshooting can stop after verification.
6. Verify Water Supply Conditions
Confirm the machine has an adequate, stable water connection and that the supply hose is not kinked, leaking, disconnected, or affected by an obvious facility water issue.
Compare with nearby dialysis machines when appropriate to determine whether multiple machines are experiencing the same problem.
Expected outcome: A machine-specific versus facility-wide water problem is identified. If multiple units are affected, escalate the water or infrastructure issue rather than assuming an individual machine failure.
7. Check Setup and Operating Configuration
Verify the treatment or preparation setup has not been entered incorrectly and that the selected concentrate configuration matches the intended clinical setup.
Do not make unauthorized configuration or service-menu changes to force conductivity into range.
Expected outcome: User-accessible settings and concentrate selections agree with the intended setup.
8. Use Known-Good External Supplies
When permitted, repeat preparation using known-good approved concentrate containers and normal water supply conditions. Observe whether conductivity stabilizes without repeated fluctuation.
Expected outcome: The fault either follows an external supply item or remains with the machine. If known-good supplies correct the condition, replace the defective or incorrect external supply and stop troubleshooting after verification.
9. Perform Final Functional Verification
Allow the machine to complete its normal preparation and verify conductivity remains stable through the required operational checks without recurrent alarms.
Do not return a machine to service based on a brief momentary normal reading after repeated instability.
Expected outcome: Conductivity remains stable throughout the required verification period and no related alarms recur. Troubleshooting can stop.
If the Problem Persists
If concentrate type, pickup, connectors, water supply, setup, and known-good external supplies have been ruled out, the remaining cause may involve an internal proportioning, sensing, hydraulic, control, calibration, or configuration problem.
The device should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
- Evaluated using appropriate Fresenius Medical Care documentation and approved test equipment.
- Repaired, calibrated, or configured only by qualified personnel.
- Fully verified for dialysate preparation and applicable safety functions before return to service.
Knowing when to stop external troubleshooting is especially important when dialysate composition cannot be independently trusted.
Clinical Use Tip
Never normalize or ignore an unstable conductivity indication simply because the machine intermittently returns to an acceptable display.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Dialysis staff reported conductivity would not stabilize during preparation on the 5008S CorDiax."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the concentrate pickup connection was not fully seated and was intermittently drawing air."
Resolution
What action was taken.
Example:
"The connection was properly seated, preparation was repeated, conductivity remained stable through functional verification, and the machine was returned to service."
Helpful Details to Include (If Known)
- Whether conductivity was high, low, or unstable.
- Exact displayed message.
- Concentrate products connected.
- Container levels and condition.
- Pickup tubing and connector condition.
- Water supply condition.
- Whether other machines were affected.
- Known-good concentrate substitution.
- Results before and after correction.
- Final device status.
Final Thought
Dialysate conductivity problems require conservative troubleshooting: protect the patient, verify concentrate and water sources first, confirm the full external setup, and escalate rather than assuming or overriding an unresolved condition.
That is successful troubleshooting.