Quick facts
- ISO 15189:2022 treats equipment as a resource requirement: Clause 6.4 covers equipment and Clause 6.5 covers equipment calibration and metrological traceability. The laboratory must define the intervals; the standard does not supply a universal calendar.
- Pipettes belong to the piston-operated volumetric apparatus family covered by ISO 8655-1:2022, and the gravimetric reference method is ISO 8655-6:2022.
- ISO 8655-6 defines how to test, not how often. A schedule that cites the standard but cannot say why the interval is six months rather than twelve has not answered the accreditation question.
- A balance used for analytical work needs a daily check against a traceable weight and a periodic calibration by a competent provider; ISO/IEC 17025:2017 is the standard to look for in that provider's scope.
- A centrifuge has no single calibration standard. Speed, time and temperature are verified against the manufacturer's specification, and the rotor and trunnions are inspected at the same visit.
- Clause numbers and standard titles were read on 2026-10-19; the interval table is a template for a laboratory's own risk assessment, not a regulatory prescription.
A calibration schedule is one of the few laboratory documents that an assessor can use to reconstruct how the lab thinks: it shows which measurements the lab believes are fragile, how quickly it expects drift, and what it does when a check fails. ISO 15189 requires the schedule without prescribing it, which is why laboratories that copy a generic twelve-month table often cannot defend it. This article sets out the method for pipettes, balances and centrifuges, the records each one needs, and the risk matrix that turns a supplier's recommendation into a defensible interval; the pipettes and sealing film in the same workflow are listed in the laboratory consumables pack.
Tubes that ride the same rotor: sterile 15 mL graduated centrifuge tubes with screw caps, 500 per case are the consumable loaded into the centrifuge whose speed, time and temperature are verified on this page.
What does ISO 15189 actually require for calibration?
The 2022 edition places equipment in Clause 6.4 and equipment calibration and metrological traceability in Clause 6.5. The requirement is not a table of intervals. It is a system: the laboratory identifies the equipment that can affect the validity of results, defines how each item is verified, defines the interval at which verification or calibration is repeated, and keeps records that show the interval was followed.
That structure has a practical consequence. The assessor is not checking whether the lab used six months or twelve. The assessor is checking whether the lab can explain the choice, whether the records match the written schedule, and whether a failed check triggers an investigation into results reported since the last good check.
Metrological traceability is the second half. A calibration certificate is only useful if the values on it trace to a national or international reference through an unbroken chain of calibrations. That is why the certificate should name the provider's scope and the reference weights or methods used, not only the pass or fail result.
Why is there no universal interval for a pipette?
ISO 8655-1 sets out the general requirements for piston-operated volumetric apparatus, and ISO 8655-6 sets out the gravimetric reference measurement procedure. Neither says that a pipette must be checked every three, six or twelve months, because the drift depends on the liquid, the number of cycles, the operator, the tip fit and the cleaning routine.
What the standards do say is how to test. The gravimetric method weighs dispensed water on a balance, corrects for temperature and evaporation, and expresses the result as systematic error and random error against the manufacturer's limits. Testing at a single volume near the maximum tells you very little about the small-volume transfer the method depends on, so the schedule should name the test volumes.
A defensible interval therefore combines three inputs: the manufacturer's recommendation, the operator's cycle count, and the lab's own history of failures. A pipette used daily with volatile solvents belongs on a shorter interval than one used weekly with aqueous buffer, and the file should say so.
| Item | What is verified | Reference document | Interval logic |
|---|---|---|---|
| Air-displacement pipette | Systematic and random error at defined volumes | ISO 8655-1, ISO 8655-6 | Manufacturer recommendation, cycle count, solvent, failure history |
| Positive-displacement pipette | Same, with the tip and seal as part of the system | ISO 8655-1, ISO 8655-6 | Shorter where viscous or volatile liquids are used |
| Analytical balance | Accuracy and repeatability against traceable weights | ISO/IEC 17025 provider scope | Daily check, periodic calibration, after relocation or repair |
| Centrifuge | Speed, time, temperature, rotor condition | Manufacturer specification | Annual service plus check after imbalance or rotor change |
| Thermometer or incubator | Temperature at the working point | Traceable reference | Periodic verification, plus daily temperature record |
How should a pipette be tested?
Use the gravimetric method on a balance that is adequate for the volume. For a 10-100 µL pipette the balance needs a resolution fine enough that the weighing uncertainty is small relative to the tolerance; for a 1 mL pipette the requirement is looser. The test liquid is water at a controlled temperature, and the evaporation trap matters more at small volumes than at large ones.
Test at least three volumes across the working range, including one near the lower limit, and calculate the mean and the standard deviation against the manufacturer's accuracy and precision limits. A pipette that passes at 100 µL and fails at 10 µL is not a passing pipette; it is a pipette that will fail the small-volume step of the method.
Record the serial number, the tip lot if the method is tip-sensitive, the water temperature, the balance identifier, the test volumes, the mean, the standard deviation and the pass or fail decision. If the pipette fails, quarantine it, identify the last good check and assess the results reported in between. The assessment is the part an assessor reads most closely.
What does a balance need beyond an annual calibration?
A balance drifts with temperature, vibration, draughts and level. The daily check is a single traceable weight placed at the centre of the pan, recorded, and compared with the previous day. That check catches a balance that has been moved, levelled badly or left with a draught across the pan; it does not replace the periodic calibration.
The periodic calibration should be performed by a provider whose scope covers the range and the uncertainty the lab needs, which is where ISO/IEC 17025 comes in. The certificate should state the as-found and as-left values, the uncertainty, the traceability chain and the environmental conditions. A certificate that reports only 'pass' is a certificate the lab cannot use to assess drift.
Balances used in trade, such as a retail scale, fall under a different regime administered by Measurement Canada. A laboratory balance used for analytical work is not a trade instrument, but the distinction is worth knowing before a buyer assumes that a trade seal is a calibration certificate.
What is verified on a centrifuge?
A centrifuge is verified against the manufacturer's specification for speed, time and temperature. Speed is checked with a tachometer or the service software; time is checked with a stopwatch or the service routine; temperature is checked with a calibrated probe at the working set point, not at the display.
The mechanical inspection matters as much as the electronics. Rotor cracks, corroded trunnions, worn O-rings and missing buckets are the failure modes that produce imbalance and, in the worst case, a rotor failure. The service visit should include the rotor log, the maximum cycle rating and the retirement date where the manufacturer specifies one.
The interval is usually annual for a routine clinical centrifuge, shorter for a high-throughput or high-speed unit, and always after an imbalance event, a rotor change or a move. The record should name the rotor, the speed tested, the time tested, the temperature tested and the action taken.
| Check | Method | Acceptance | Record |
|---|---|---|---|
| Speed | Tachometer or service software | Within manufacturer tolerance at the set speed | Set speed, measured speed, rotor |
| Time | Stopwatch or service routine | Within manufacturer tolerance | Set time, measured time |
| Temperature | Calibrated probe at working set point | Within specification after equilibration | Set point, measured value |
| Rotor condition | Visual and dimensional inspection | No cracks, corrosion or wear beyond limit | Rotor serial, hours, action |
| Imbalance safety | Check of trunnions, buckets and O-rings | Free movement, no deformation | Parts replaced |
How do you turn this into a schedule an assessor will accept?
Build a matrix with one row per instrument and four columns: the measurement that matters, the verification method, the interval, and the trigger for an unscheduled check. The interval should be justified in one sentence that references the manufacturer's recommendation and the lab's own failure history. The trigger column covers the events that invalidate the last check: relocation, repair, a failed daily check, a new operator, a new tip type.
Then map the records. Each row should point to the log or certificate that proves the check happened, and the log should be retrievable by instrument serial number. An assessor who can pull one instrument's file and see the schedule, the certificates, the daily checks and the corrective action has seen the whole system.
Finally, review the schedule annually. A schedule that has never been revised is either perfect or unexamined, and the second is more common. The review should use the failure data the lab already has: how many pipettes failed, which volumes failed, which centrifuge needed a repair, which balance drifted.
A calibration programme runs on consumables as well as certificates. Order through the wholesale programme for case pricing and an account, or become a distributor for resale. The laboratory pipette and sealing film pack sits in the same catalogue. Consumables for this line are listed under the department page.
Sources
- ISO 15189:2022, medical laboratories, requirements for quality and competence
- ISO 8655-1:2022, piston-operated volumetric apparatus, terminology and general requirements
- ISO 8655-6:2022, gravimetric reference measurement procedure for piston-operated volumetric apparatus
- ISO/IEC 17025:2017, competence of testing and calibration laboratories
- ISO 13485:2016, medical devices quality management
- ISO 14971:2019, application of risk management to medical devices
- Measurement Canada
- CLSI, quality management documents
- CLSI GP41 companion quick guide, venous specimen collection
- Public Health Ontario, infection prevention and control
- Health Canada, medical devices
- Health Canada, establishment licensing
- Medical Devices Regulations, SOR/98-282
- Standards Council of Canada
- CSA Group, standards catalogue
- World Health Organization, guidelines on drawing blood
- Canadian Association of Optometrists
- Royal College of Dental Surgeons of Ontario, standards and guidelines
Printable calibration schedule template. One page per instrument, with the method, the interval, the acceptance limit and the certificate number in adjacent columns. Print a calibration schedule sheet - the layout follows the order an assessor reads, and it prints with no account and no sign-up.
Log generator. Turn the schedule into dated rows for the year, so that a missed pipette check appears as a gap. Build a calibration calendar - choose the instrument class and the interval and the page lays out the months, the certificate column and the corrective-action column.
Ask a compliance specialist. Whether an interval is defensible depends on the method, the cycle count and the lab's own failure history, not on a generic table. Ask a compliance specialist - written answer specific to your equipment and province, with the regulation or standard it is based on cited.
Related reading
- Laboratory centrifuges in Canada and the US: which class applies
- Microcentrifuge tubes in Canada and the US: which standards and labelling apply
- Capillary tubes in Canada and the US: which size and standard should a lab specify
CliniEco Medical supplies eye care, laboratory and dental consumables of the kind described in this article. MDEL #35334. This article is written for laboratory managers and quality officers and is not legal advice; the calibration intervals a laboratory adopts are its own, and they must be justified in its quality management system.
Frequently Asked Questions
Does ISO 15189 set calibration intervals?
No. ISO 15189:2022 requires the laboratory to define equipment, calibration and metrological traceability in Clauses 6.4 and 6.5, but it does not prescribe a universal calendar. The laboratory must justify the interval it chooses.
How often should a pipette be calibrated?
There is no single answer. The interval depends on the manufacturer's recommendation, the number of cycles, the liquid and the laboratory's failure history. The test method is ISO 8655-6; the interval is the laboratory's risk decision.
At which volumes should a pipette be tested?
At least three volumes across the working range, including one near the lower limit. A pipette that passes at the maximum volume but fails near the minimum is not suitable for methods that rely on small transfers.
What is checked on a centrifuge?
Speed, time and temperature against the manufacturer's specification, plus the condition of the rotor, trunnions, buckets and O-rings. The check is repeated after an imbalance, a rotor change or a move.
Does a balance need a daily check?
A daily check against a traceable weight catches drift, levelling problems and draughts. It does not replace the periodic calibration by a competent provider whose scope covers the range and uncertainty the laboratory needs.
What should a calibration certificate contain?
The as-found and as-left values, the uncertainty, the traceability chain, the environmental conditions and the provider's scope. A certificate that reports only pass or fail cannot be used to assess drift.
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