Centrifuge qualification: speed, temperature and time

Define the system being qualified

Qualification concerns the centrifuge as used: main unit, rotor, buckets, adapters, vessels, sensors, programmes and permitted loads. Identify every configuration and the method using it. A report referring only to the machine’s serial number may leave the actual scope of verification unclear.

In pharmaceutical operations, EU GMP Annex 15 provides a framework for planning qualification proportionate to risk throughout the lifecycle. Apply it within the site quality system; do not turn IQ, OQ and PQ into three certificates disconnected from use. Safety remains a prerequisite for every test.

Keep the terms distinct: calibration characterises the relationship between indications and references, with their uncertainties; verification compares evidence against requirements; adjustment changes the system. Qualification integrates documents and tests to demonstrate intended suitability. None of these activities automatically replaces another.

Translate intended use into critical requirements

Start with samples, the fraction to recover, speed and time ranges, thermal conditions, throughput and risks. Determine which functions could compromise identity, stability, recovery or reproducibility. “Centrifuge cold” is too vague: specify a sample condition, a relevant period and a verifiable criterion.

Define test points and configurations representing the operating range. Justify extremes, representative loads and repetitions according to risk and expected variability; do not select a standard number of tests without explanation. A challenging cooling configuration may not be the most challenging for speed stability.

For every requirement, identify the criterion’s source: developed method, stability data, approved requirements or applicable specification. A broad instrument specification may not protect the method. Maintain the link to rotor, radius and RPM–RCF conversion.

Confirm installation and prerequisites

Installation verification identifies components and accessories and checks location, support, power and environmental conditions against design and instructions. Collect relevant manuals, programme configuration, safety documentation, planned maintenance and the status of measurement references.

Before testing, confirm that rotor, accessories and load are permitted, intact and correctly installed. Trained personnel must know stopping procedures, fault handling and responsibilities. Functional testing of protective devices follows authorised procedures: do not induce a dangerous failure to demonstrate that protection operates.

IEC 61010-2-020:2026 is the specific safety standard for electrically powered laboratory centrifuges; its consulted public record defines the scope. Do not infer qualification tolerances or automatic model certification from that record. System documentation must clarify permitted testing conditions.

Verify speed and time without defeating protection

For speed, choose a comparison method intended for the machine and a reference with suitable range, resolution and uncertainty. Optical measurement is usable only through a purpose-designed, authorised access point; do not lift the lid, defeat interlocks or attach improvised rotor markers. If safe access is unavailable, involve qualified personnel using a compatible method.

Record setpoint, indication, reference result, rotor, load and reading time. One stabilised reading does not automatically describe the ramp or stability over the entire cycle. If converting the result into RCF, also document radius, units and the convention used.

For time, define start and finish events: programme initiation, reaching speed, end of the hold and complete stopping are different events. Compare the same interval against a suitable time reference and consider resolution and uncertainty in identifying events. Retain original data, not just “timer compliant”.

Separate indication, chamber and sample temperature

The setpoint is a command; the indication is what the system reports; a chamber measurement concerns a location; sample temperature concerns the matrix in its vessel during the cycle. Sensor calibration alone does not demonstrate equivalence between these quantities.

Plan starting conditions, any preconditioning, volume, load, positions and the observation period. The measurement method needs suitable response and uncertainty and must not materially alter the behaviour being assessed. Document what a sample substitute represents and what differences remain.

Do not put unauthorised probes, cables or loggers into rotating parts. A measurement after stopping may be useful but does not establish the entire profile during the run: opening and reading delay may change it. If the requirement covers the complete cycle, agree on a suitable safe solution or explicitly limit the conclusion.

NIH research on analytical ultracentrifugation illustrates why measurement location and thermal evolution matter. Its experimental devices and mechanical modifications are not instructions to transfer to a routine centrifuge.

Link each test to the release decision

The following original matrix is a model to adapt. Criteria must be approved before execution; it contains no universal tolerances.

Evaluate uncertainty against the decision to be made and explain how results close to a limit will be handled. Metrological traceability alone does not guarantee fitness for purpose. Specify certificate ranges and conditions, any corrections and the limitations of the comparison method.

An application test may show that separation works; it does not automatically verify every instrument function. Conversely, compliant speed and timing do not demonstrate recovery or sample integrity. Review the evidence together, record deviations and their impact, then formalise approval and the authorised scope. Do not make an outcome acceptable by changing the criterion afterwards without justification and documented control.

Review changes and load configurations

Simulated case: the laboratory moves from a few small-volume tubes to a configuration with greater total volume, keeping the setpoint and programme. The previous report documented only the first load. It does not automatically establish the thermal behaviour of the new assembly, although it remains useful for functions and conditions actually covered.

The responsible person compares vessels, adapters, mass, starting conditions and duration, assesses sample risk and defines targeted supplementary tests. The new configuration enters authorised use only after relevant evidence and approval. Indiscriminately repeating everything is unnecessary: explain what remains valid and why.

Apply the same reasoning to significant maintenance, rotor replacement, relocation, control updates or method changes. Review and requalification intervals depend on risk, use, instructions and performance history. Connect findings to preparation records and the liquid handling and sample preparation hub.

For the related steps, see: Centrifuge maintenance: vibration, rotors and faults.

Sources and scope

• EU GMP Annex 15, 2015: planning, qualification, deviations and changes; operative from 1 October 2015.
• JCGM 200:2012, VIM: calibration, verification and traceability.
• NIST — Metrological Traceability: traceability, uncertainty and fitness for purpose.
• Zhao et al., 2014 — Rotor Temperature in Analytical Ultracentrifugation: original NIH study; specific scope, no mechanical procedure transferred.
• IEC 61010-2-020:2026: public record and scope, not the full text.