For which laboratory instruments should preventive maintenance procedures be performed and recorded?

• A. Analytical balance
• B. Centrifuge
• C. Chemistry analyzer
• D. All the above

Answer: (D)

Regular preventive maintenance with documented records is essential for any instrument that directly affects measurement quality and lab safety. An analytical balance can drift over time, so maintenance includes calibration with standard weights, verification of zero and repeatability, and cleaning, with results and adjustments recorded. A centrifuge relies on precise rotor performance and speed; maintenance involves inspecting rotors for cracks, ensuring proper balancing, verifying operating speeds, checking lid interlocks, and logging the service and findings. A chemistry analyzer is a complex automated system where accuracy depends on multiple subsystems; maintenance covers cleaning probes and cuvettes, checking reagents, calibrating with standards, running quality control, updating software, and keeping a thorough maintenance log. Recording these activities creates traceability, supports quality compliance, helps schedule future upkeep, and aids in investigating any data discrepancies. Therefore, all of the above instruments should have preventive maintenance procedures performed and recorded.