Beckman Coulter AU480: sodium (Na) electrode failure in the ISE module
What happened
The sodium electrode in the ISE module stopped working and no longer gave usable Na readings.
What was checked
- Rinsed the electrodes with Beckman cleaner, driving the fluid through manually with the peristaltic pump.
- Flushed with deionized water two to three times, as reported in the case.
- Ran a standard wash cycle and then the electrolyte test.
Cause
No root cause was confirmed in this case; the engineers suspected heavy deposit build-up on the electrode membrane or ordinary electrode exhaustion.
The cause is probable and was not fully confirmed.
What was done
The reported recovery attempt: pour Beckman cleaner into the cup, draw it through the electrode path by rotating the peristaltic pump by hand, let it soak for about 30 minutes (as reported in the case), then rinse with deionized water, run a standard wash and repeat the electrolyte test. With light contamination the electrode may recover — the outcome was probable, not guaranteed; a heavily worn electrode will still need replacement.
Safety
Wear gloves and eye protection — the ISE fluid path carries biological material and the cleaner is an aggressive chemical — and confirm Na results with control materials before returning the analyzer to use.
Lesson: Before ordering a new ISE electrode, a cleaning soak with the manufacturer's cleaner is a cheap, low-risk attempt — but treat recovery as probable and validate the electrode with controls.
Covered in the course: Lab Analyser Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.