Quick facts
- A microplate reader is a benchtop photometer that measures the light that passes through or is emitted by the wells of a microplate.
- United States: the instrument is filed as a clinical spectrophotometer. 21 CFR 862.2300 covers a colorimeter, photometer or spectrophotometer for clinical use and places it in Class I.
- United States: the same entry describes an instrument intended to measure radiant energy emitted, transmitted, absorbed or reflected under controlled conditions, and allows for a monochromator to produce light of a specific wavelength.
- Canada: there is no named entry for the reader. An active instrument that reads a sample rather than the patient falls to Class I under Rule 12 of Schedule 1 to the Medical Devices Regulations, SOR/98-282.
- The clause that lifts the class in Canada is Rule 7(2)(a): a device intended to act as a calibrator, tester or quality control support to another medical device is Class II.
- The device class answers one question only; the test's complexity under CLIA in the United States and the licence a laboratory holds in Canada are separate questions.
A microplate reader looks like a lab appliance with a screen, and it is easy to treat its paperwork as an afterthought. That assumption breaks down in two places: the reader shares a regulatory entry with colourimeters and spectrophotometers, and the plate it reads can be in a different entry again. This article sets out what the instrument measures, how each country files the reader and its accessories, and what a laboratory should confirm before it buys or validates one.
What does a microplate reader measure?
A reader passes light into each well of a plate and measures what comes back. A photometer measures the light that passes through the sample; a colorimeter filters a fixed band of wavelengths; a spectrophotometer spreads the light and selects a narrow band with a monochromator. 21 CFR 862.2300 describes a colorimeter, a photometer, or a spectrophotometer for clinical use as an instrument intended to measure radiant energy emitted, transmitted, absorbed, or reflected under controlled conditions, and notes that the device may include a monochromator to produce light of a specific wavelength.
Three properties decide what the instrument can do:
- Wavelength range and selection. Filter-based and monochromator-based instruments suit different assays.
- Detection mode. Absorbance, fluorescence and luminescence are different optics, and a reader is usually built around one or two of them.
- Plate handling and documentation. The plate format and the data export are part of the record a laboratory keeps.
The plate itself is a separate article from the reader. Where a plate is sold for a specific medical use, it can reach the general-purpose laboratory entry and its own classification; where it is sold as generic plasticware it can sit outside the device framework altogether.
How do the Canadian and United States rules classify a reader?
The United States has a named Class I entry that reaches the instrument directly. Canada reaches the same class through the general rule for active devices.
| Item | Canada | United States |
|---|---|---|
| Entry that catches the reader | None; class derived by rule | 21 CFR 862.2300, colorimeter, photometer or spectrophotometer for clinical use, Class I |
| What drives the class | Active device not caught by another rule, Rule 12 | The device definition itself |
| Method-specific assay devices | Governed by their own entries | Governed by their own entries |
| Plate sold for a specific medical use | Rule 7(1) or a specific rule, Class I at base | General-purpose laboratory equipment entry, Class I |
| Calibrator, filter or reference standard | Rule 7(2)(a), Class II | Handled through the general provisions of the part |
| Premarket position | Licence only where the derived class requires one | Exempt from premarket notification, subject to 21 CFR 862.9 |
| Wording that decides the case | Any other active device | Measures radiant energy under controlled conditions |
In the United States the reader is caught by a section written for clinical colour measurement. The entry covers a colorimeter, photometer or spectrophotometer for clinical use, and it names the measured quantity, radiant energy under controlled conditions, rather than any particular assay. That is why a plate reader, a cuvette reader and a bench colorimeter can share one entry.
Canada reaches the class by rule. Rule 12 of Schedule 1 states that any other active device is classified as Class I. A plate reader is active, but it does not emit ionizing radiation, does not administer or withdraw energy to or from the body, and does not supply energy to image or monitor a physiological process in the sense Rule 10 uses, because the light it shines lands on the sample rather than on the patient. It therefore falls to Rule 12 and stays at Class I, the same class the United States gives it.
Which instrument types share the entry, and what does each measure?
| Instrument | What it measures | Class note |
|---|---|---|
| Filter colorimeter | Radiant energy through a fixed band | Class I; US entry 862.2300; Canada Rule 12 |
| Bench photometer | Transmitted or reflected light | Class I; the same US entry |
| Spectrophotometer with monochromator | A narrow selected wavelength band | Class I; the entry names the monochromator |
| Microplate reader | Light from the wells of a plate | Class I; the same entry, one instrument among several |
| Atomic absorption spectrophotometer | Absorbed light in a flame or furnace | A separate US entry; check the class before assuming Class I |
| Reference filter or standard | A known value for verification | Rule 7(2)(a) can move this to Class II in Canada |
The list is the reason a laboratory should not assume that every light-measuring instrument on the bench is the same device. A microplate reader and an atomic absorption spectrophotometer both measure light, but they are different articles, and a reference standard sold with one of them can be a higher class in Canada than the instrument it verifies.
Does the device class tell you the test complexity?
No, and this is the most common mix-up in the category. The device class is about the instrument; the complexity of the test that uses it is a separate regulatory question. In the United States the complexity of a laboratory test, from waived to moderate and high, sits in the CLIA regulations and is separate from the device entry. In Canada the equivalent question is the licence and the accreditation scope a laboratory holds. A reader that is Class I on both sides of the border can still be used for a test that a laboratory is not licensed to run, and the reverse is also true.
Four consequences follow for a laboratory:
- The reader and the plate are separate lines. Buy them as one method, but record them separately.
- The reference standard has its own class. A verification filter or standard can be Class II in Canada.
- The method file holds the wavelength and the plate. The reading conditions belong with the result.
- The licence scope is the real gate. Check it before the instrument is bought, not after.
Which consumables does a plate bench go through?
A plate bench restocks plates, pipette tips, specimen containers, gloves, disinfectant and waste bags in the same cycle. For laboratories buying at case level, the wholesale ordering page sets out account and case terms, and the B2B wholesale collection lists the lines held for institutional buyers. The 120 mL sterile specimen container, 100 per pack is the kind of line we hold for bench and collection work, and laboratories that also run an in-house sterilizer can start with the biological indicator 5-pack trial and read the sterilization monitoring collection for the monitoring lines.
Sources
- 21 CFR 862.2300, colorimeter, photometer, spectrophotometer for clinical use
- Medical Devices Regulations, SOR-98-282, full text, Schedule 1
- Health Canada, medical devices
- ISO 15189:2022, medical laboratories, requirements for quality and competence
- ISO 8655-2:2022, piston-operated volumetric apparatus, pipettes
- 21 CFR 864.3600, microscopes and accessories
- Public Health Ontario, laboratory test information index
- Public Health Ontario, infectious diseases
- Clinical and Laboratory Standards Institute
- Institute for Quality Management in Healthcare
- College of Medical Laboratory Technologists of Ontario
- Ontario, Laboratory and Specimen Collection Centre Licensing Act
- Canadian Centre for Occupational Health and Safety, OSH answers
- CCOHS, personal protective equipment
- World Health Organization, laboratory biosafety manual
- openFDA device classification database
- FDA device classification database search
- FDA CLIA waived analytes database
- US OSHA bloodborne pathogens standard, 1910.1030
- World Health Organization, oral health fact sheet
Related reading
- P20 Pipette: Which Volume Range Suits Small-Volume Laboratory Work
- P1000 Pipette: Which Volume Range and Tip Colour Does Your Lab Need
- Laboratory Water Baths in Canada vs the US: Which Rules Apply
- Phase Contrast Microscopes in Canada vs the US: Which Standards and Rules Apply
CliniEco Medical supplies laboratory and clinic consumables of the kind described in this article. MDEL #35334. This article is written for laboratory, procurement and quality professionals and is not clinical or accreditation guidance; method validation and result interpretation belong to the laboratory director.
Frequently Asked Questions
Is a microplate reader a medical device in the United States?
Yes, when it is intended for clinical use. 21 CFR 862.2300 covers a colorimeter, photometer or spectrophotometer for clinical use, which is an instrument intended to measure radiant energy emitted, transmitted, absorbed or reflected under controlled conditions, and places it in Class I.
How is a microplate reader classified in Canada?
As an active device that does not fall under the imaging, energy-withdrawal or radiation rules, it is Class I under Rule 12 of Schedule 1 to the Medical Devices Regulations, which states that any other active device is classified as Class I.
Does a monochromator change the class?
No. The United States entry for a clinical spectrophotometer names the monochromator as an optional part of the instrument, and the device stays in Class I. In Canada the added optics do not change the rule path.
Can an accessory to a reader be Class II in Canada?
Yes. Rule 7(2)(a) classifies a device as Class II when it is intended to act as a calibrator, tester or quality control support to another medical device, so a reference filter or verification standard sold for the reader can be Class II even though the reader is Class I.
Does the device class tell me whether a test is waived or complex?
No. The device class is about the instrument. In the United States the complexity of a laboratory test is set in the CLIA regulations, and in Canada the equivalent question is the licence and accreditation scope a laboratory holds. The two questions are separate.
What should a laboratory keep on file for a plate reader?
The wavelength and detection mode the method uses, the plate format, the reference filter or standard and its check interval, and the method file that records the reading conditions with the result. The record belongs in the equipment or method file, not the purchase file.
Do colourimeters and photometers use the same entry as a plate reader?
In the United States, yes. 21 CFR 862.2300 covers a colorimeter, photometer or spectrophotometer for clinical use, and the entry names the radiant energy measured rather than any particular format, so a cuvette reader, a bench colourimeter and a plate reader can share the same section.
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