The World Health Organization has published a nationwide preventive maintenance programme intended to support laboratory equipment management across member-state health systems.

In practice, a PM programme covers scheduled inspection, cleaning, performance verification, and parts replacement — the operational layer that keeps clinical analyzers, spectrophotometers, centrifuges, and thermocyclers inside their manufacturer-stated accuracy envelopes between formal calibration events. The two activities, PM and calibration, are not the same; PM preserves performance between calibrations, while calibration re-ties the instrument to a measurement standard.

What does the programme cover?

Preventive maintenance is schedule-driven; corrective repair is failure-driven. Both occur in an instrument's life cycle, but only PM creates the documentation chain that accreditation auditors actually examine during a surveillance visit.

A standard PM visit on a clinical chemistry analyzer walks through a defined checklist:

• Photometer lamp output and wavelength check against a holmium-oxide or didymium reference
• Reagent and sample probe cleaning or replacement
• Pump head, valve, and tubing leak test under operating pressure
• ISE reference electrode slope and response verification
• QC material run against the analyzer's assigned target values, with Levey-Jennings charting

Each line item carries a date, a technician signature, and the device's serial number. That triad links a specific instrument to a specific patient result, and it is what ISO/IEC 17025 and ISO 15189 audits look for on site.

Why is uptime the wrong primary KPI?

Lab managers commonly quote equipment uptime as evidence of a working maintenance operation. Uptime measures availability, not accuracy. A centrifuge can spin without failure for years while its tachometer drifts enough to push relative centrifugal force outside the validated range of a published diagnostic protocol. A spectrophotometer can pass a wavelength check at 546 nm while drifting badly at 260 nm, where nucleic acid quantification lives.

Three metrology-grade indicators carry more weight in any programme review:

1. Mean time between failures, stratified by failure mode — mechanical, electronic, software, consumable
2. Fraction of instruments holding a current calibration certificate traceable to a national metrology institute
3. Count of out-of-tolerance QC events caught between scheduled PM visits

What do the existing standards already require?

ISO/IEC 17025:2017 requires laboratories to keep equipment in a "fit for purpose" condition with documented records. ISO 15189:2022 carries the same expectation into medical laboratories. The WHO programme, in instrumentation terms, reads as an operational template for satisfying the maintenance and record-keeping clauses those standards already impose on accredited facilities.

Buyers of laboratory equipment in a country adopting the framework will need to ask which clauses the vendor's service documentation actually supports — electronic PM logs with cryptographic signatures, signed service records, calibration certificates traceable to a national metrology institute, and remote access for firmware update verification.

What does the plan ask of national budgets?

Adoption turns on three resources the document cannot supply on its own: a trained biomedical engineering workforce, a funded spare-parts pipeline, and a LIMS configuration that ingests machine-readable PM records without manual transcription. A lab that runs the programme on paper will struggle at the next surveillance audit, regardless of how faithfully its technicians perform the work.

The compliance question for hospital procurement officers is direct. When the next tender crosses the desk, will the vendor's service contract produce the documentation the WHO record format expects, and will the lab's existing information system consume it without transcription error — or will the biomedical engineering team end up re-keying service reports by hand?