A serological pipette is a measuring instrument, and the number printed on its side is only meaningful if the buyer knows what the nominal capacity refers to. The same 10 mL marking can mean "this pipette will deliver 10 mL" or "this pipette holds 10 mL," and the two are not interchangeable in a dilution, a standard curve or a quality-control record.
That distinction, and the class the pipette was manufactured to, is what the standards cover. For a clinic, veterinary laboratory or research bench buying pipettes by the case, the useful questions are narrower than the standards: which class, which colour band, which format, and what documentation the laboratory's accreditation expects. The Canadian and US answers to the last question differ, because the laboratories themselves are overseen differently.
What makes a pipette a serological pipette?
A serological pipette is a graduated pipette with a scale that runs to the tip and a graduation designed so the instrument delivers the volume it says. The scale is not arbitrary: ISO 1769:1975 specifies "a system of color coding for one-mark pipettes for identification of nominal capacities, and for graduated pipettes for identification of nominal capacities and unit of subdivision."
That single sentence explains why a pipette has a coloured band at the mouth end. The band is not decoration and it is not a brand marker. It encodes the nominal capacity and the subdivision, so a bench worker can identify a pipette at arm's length without reading a scale that has been wetted.
The families on a laboratory bench are easy to confuse, so it is worth separating them.
| Pipette family | How it is scaled | What the marking refers to | Typical use |
|---|---|---|---|
| Serological, graduated to deliver | Scale to the tip | Volume delivered | Cell culture, dilutions, reagent transfer |
| One-mark volumetric | Single ring mark | Volume contained | Preparing standard solutions |
| Piston pipette with tip | Set volume | Volume delivered, Ex | Micro-volumes, routine dispensing |
| Pasteur or transfer pipette | Uncalibrated | Not a measuring instrument | Transfer without measurement |
The serological pipette sits in the middle: it is a measuring instrument, but the last drop stays in the tip unless the pipette is marked as blow-out. That single design fact is why a 10 mL serological pipette and a 10 mL volumetric pipette cannot be used interchangeably when a protocol states a tolerance.
Which class applies, and who defines it?
The graduating standard for glass pipettes is ISO 835, and its two parts split the job.
ISO 835-2:1981 sets out the special requirements: "The special requirements deal with three international acceptable series of pipettes (type 1, 2, and 3) which are adjusted to class A or class B accuracy. Capacity, graduation, delivery times are specified."
ISO 835-1:1981 covers the general requirements and the waiting time: "Pipettes with no waiting time and with waiting time of 15 s and such ones adjusted for blow-out are generally concerned and specified. Limits of error for class A pipettes are shown in relation to capacity."
Piston pipettes — the adjustable instruments with disposable tips — are covered by a different standard. ISO 8655-2:2022 specifies "metrological requirements, maximum permissible errors, requirements for marking and information to be provided for users, for air-displacement (type A) and positive displacement (type D) single-channel and multi-channel pipettes, complete with their selected tip(s)" and adds that they are "designed to deliver the selected volume (Ex)."
The practical consequence of the Ex marking is worth stating in the purchasing note: a piston pipette's accuracy is defined with a specific tip fitted, so a substitute tip is a change to the measuring instrument, not a consumable swap.
Do Canada and the US oversee the laboratory the same way?
This is where a buyer gets misled, because the pipette is a general laboratory instrument in both countries while the laboratory that uses it is not overseen the same way at all.
| Item | Canada | United States |
|---|---|---|
| Pipette standards | ISO 835-1 and 835-2 for glass; ISO 8655-2 for piston | Same international standards |
| Colour coding | ISO 1769:1975 | ISO 1769:1975 |
| Laboratory oversight | Provincial licensing and accreditation, e.g. the Laboratory and Specimen Collection Centre Licensing Act (R.S.O. 1990, c. L.1) in Ontario | CLIA certification under 42 CFR part 493 |
| Test complexity tiers | Defined by the licence and accreditation scope | Waived, moderate complexity, high complexity |
| Quality management standard | ISO 15189 for medical laboratories | CLIA conditions plus optional accreditation |
| Buyer's first question | Which licence and accreditation do you hold? | What is your CLIA certificate? |
The US tiering is explicit. 42 CFR 493.1 sets out "the conditions that all laboratories must meet to be certified to perform testing on human specimens under the Clinical Laboratory Improvement Amendments of 1988," 42 CFR 493.5 sorts tests into "waived," "moderate complexity" and "high complexity," and 42 CFR 493.15 addresses waived tests directly.
Canada's equivalent is not a single federal statute. Laboratories are licensed and accredited within the provincial system, and many medical laboratories hold accreditation against ISO 15189:2022, which "specifies requirements for quality and competence in medical laboratories" and is used "for confirming or recognizing the competence of medical laboratories by laboratory users, regulatory authorities and accreditation bodies."
For a pipette buyer, that difference changes the paperwork that has to exist. A US laboratory reading a pipette specification into a CLIA inspection is documenting against a certificate category. A Canadian laboratory is documenting against a provincial licence and, where it holds one, an ISO 15189 accreditation. The pipette specification is the same; the file it goes into is not.
Does a pipette count as a medical device?
A pipette used to measure a reagent is laboratory equipment, not a diagnostic product. The instrument that carries a claim about a patient result is the test system, and that is regulated separately.
In the United States, 21 CFR part 864 covers in vitro diagnostic products for human use, and 21 CFR 862.1675 shows how specific a classification can get: a blood specimen collection device is "a device intended for medical purposes to collect and to handle blood specimens and to separate serum from nonserum (cellular) components prior to further testing," and it is Class II. A buyer can check whether a specific product carries a clearance in the FDA classification database.
In Canada, classification under the Medical Devices Regulations (SOR/98-282) follows intended use and the Schedule 1 rules. A graduated pipette that measures a reagent does not carry a diagnostic claim, which is why it sits outside the device licence conversation that applies to the test kit itself.
What should a clinic order, and in what format?
Four decisions cover most orders, and each one is a question the supplier can answer from the specification sheet.
- Capacity set. A working bench usually needs 1, 5, 10 and 25 mL. Ordering a single size because it was on offer creates a bench that cannot make a 1:4 dilution without repeating a step.
- Class. Class A for work where the tolerance matters, class B where it does not. Naming the class on the order is what makes the delivery comparable between suppliers.
- Sterility and wrapping. Individually wrapped sterile pipettes for cell work and clean applications, bulk packs for reagent preparation where sterility is not the constraint.
- Plugged or unplugged. A plug stops liquid reaching the mouth end of the pipette, which is both a measurement and a safety consideration.
A laboratory consumables order is rarely only pipettes. The same delivery usually carries 90 mL graduated specimen containers for sample handling, cotton swabs for bench cleaning and sample work, and a rack of shared equipment that has to be maintained on a schedule. Grouping those lines on one purchase order is what keeps a bench supplied without a weekly emergency order.
How should pipettes be verified and recorded?
Verification is a schedule, not an event. Glass pipettes are checked against their class tolerance, piston pipettes are checked gravimetrically with the tip they are used with, and both checks produce a record with a date, a result and the instrument identity.
Three rules make that record useful at inspection:
- Identify the instrument, not the box. A record that names the case cannot be reconciled with the pipette on the bench.
- Record the tip for piston pipettes. ISO 8655-2 defines performance with the selected tip, so a check run with a different tip does not describe the instrument in use.
- Keep the waiting time with the method. A 15-second waiting time and a blow-out instruction are part of the measurement procedure, and a written method that omits them produces inconsistent results between operators.
Sources
- ISO 835-1:1981, Laboratory glassware — Graduated pipettes — Part 1: General requirements
- ISO 835-2:1981, Laboratory glassware — Graduated pipettes — Part 2: Pipettes for which no waiting time is specified
- ISO 1769:1975, Laboratory glassware — Pipettes — Colour coding
- ISO 8655-2:2022, Piston-operated volumetric apparatus — Part 2: Pipettes
- ISO 15189:2022, Medical laboratories — Requirements for quality and competence
- 42 CFR 493.1, Basis and scope of CLIA
- 42 CFR 493.3, Applicability
- 42 CFR 493.5, Categories of tests by complexity
- 42 CFR 493.15, Laboratories performing waived tests
- 21 CFR part 864, In vitro diagnostic products for human use
- 21 CFR 862.1675, Blood specimen collection device
- Medical Devices Regulations, SOR/98-282
- Laboratory and Specimen Collection Centre Licensing Act, R.S.O. 1990, c. L.1
- CLSI, Order of blood draw tubes and additives
- CLSI, Standards and resources
- Public Health Ontario, Criteria for acceptance of specimens
- WHO, Laboratory biosafety manual
- CCOHS, WHMIS and hazard communication
Ordering for a clinic, laboratory or care home? Wholesale and multi-site ordering covers account setup and case pricing, and the B2B wholesale collection lists the lines stocked for institutional buyers. Sites that also run an in-house sterilizer can start with the biological indicator 5-pack trial.
Related reading
- Ontario Laboratory Licensing: What the Laboratory and Specimen Collection Centre Licensing Act Requires
- Specimen Collection Containers for Canadian Labs: Urine Cups, Cary-Blair and 24-Hour Collection
- What Does CLSI GP41 Require for Venous Blood Collection?
Frequently Asked Questions
What is the difference between a serological pipette and a volumetric pipette?
A serological pipette is graduated to deliver, so the volume printed on it is the volume that comes out and the last drop stays in the tip unless the pipette is marked blow-out. A one-mark volumetric pipette is filled to a ring mark to contain a fixed volume, and it is used where a single accurate volume is needed.
What does the colour band on a pipette mean?
It encodes the nominal capacity of the pipette and, for graduated pipettes, the unit of subdivision. ISO 1769:1975 specifies that colour coding system for identifying nominal capacities, so the band is a specification rather than a brand marking.
What are class A and class B pipettes?
ISO 835-2:1981 describes three internationally accepted series of graduated pipettes adjusted to class A or class B accuracy, with capacity, graduation and delivery times specified. Class A carries the tighter error limits, which ISO 835-1:1981 sets out in relation to capacity.
How are Canada and the US different for laboratory accreditation?
US laboratories are certified under CLIA, with 42 CFR 493.1 setting the conditions and 42 CFR 493.5 sorting tests into waived, moderate complexity and high complexity. Canadian laboratories are licensed and accredited provincially, and many hold ISO 15189 accreditation, which specifies requirements for quality and competence in medical laboratories.
Does a pipette need a medical device licence in Canada?
A pipette that measures a reagent is laboratory equipment, not a diagnostic product. The Medical Devices Regulations classify by intended use, and a diagnostic claim sits with the test system rather than with the measuring instrument.
Why does the tip matter for a piston pipette?
ISO 8655-2:2022 specifies metrological requirements and maximum permissible errors for piston pipettes complete with their selected tips, and describes them as designed to deliver the selected volume. Because the tip is part of the measuring system, substituting a different tip changes the instrument's performance.
What is the correct waiting time for a graduated pipette?
It depends on the pipette. ISO 835-1:1981 addresses pipettes with no waiting time, pipettes with a 15-second waiting time, and pipettes adjusted for blow-out, so the method document should name the pipette type rather than assume a single waiting time.
CliniEco Medical supplies specimen containers, laboratory consumables, cotton swabs and the wider clinic and laboratory lines described in this article. Health Canada MDEL #35334. This article is written for clinic, laboratory and procurement professionals and is not clinical guidance; method selection, tolerance decisions and result interpretation belong to the laboratory director.
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