Instrumentation, Maintenance, and Troubleshooting
Instrumentation, Maintenance, and Troubleshooting tests safe operation, preventive maintenance, calibration verification, and systematic fault finding in laboratory analyzers. The exam expects a logical sequence: check the sample, check the reagent, check the instrument, then check the result.
Core rules
- Follow the operator manual and maintenance schedule; record daily, weekly, and monthly tasks.
- Distinguish calibration from calibration verification and from quality control.
- Keep sample and reagent probes clean; check for clots, bubbles, insufficient volume, and expired reagents.
- Monitor lamp hours, temperatures, tubing, and waste; use error logs and trend data.
- Before returning an analyzer to service, verify with controls, and document the fix so the next shift knows the instrument status.
Worked example
A chemistry analyzer reports low sodium and high potassium on several samples. The reasoning: check for hemolysis first, then sample volume and probe obstruction, then reagent and calibration. If controls are acceptable and only patient samples are affected, preanalytical error is likely. The fix is not a random calibration; it is a stepwise exclusion of causes.
Traps
Calibrating to hide a quality control failure, ignoring a drift trend, bypassing safety interlocks, and failing to document maintenance. Also avoid troubleshooting by replacing parts before checking the sample and reagent.