Prothrombin Time Tests in Canada vs the US: Which Class Applies?

Quick facts

• A prothrombin time test is used as a general screening procedure for clotting factor deficiencies in the extrinsic coagulation pathway, and to monitor patients receiving coumarin therapy.
• United States: 21 CFR 864.7750 places the test in Class II, and the class is expressed as performance standards rather than as special controls or general controls.
• Canada: the test is an in vitro diagnostic device, and its class turns on the setting. An IVDD intended for use outside a laboratory is a near patient IVDD, and Part 2 Rule 6 of Schedule 1 to the Medical Devices Regulations, SOR/98-282 classifies it as Class III.
• A prothrombin time test run inside a testing laboratory is classified under the patient-management rules, where the answer is Class II unless a listed exception applies.
• One exception is specifically relevant to anticoagulation monitoring: an IVDD for patient management moves to Class III where there is a risk that an erroneous result will lead to a patient management decision resulting in an imminent life-threatening situation.
• Canadian regulation text used here is current to 2026-09-21 and last amended 2026-06-17, as stated on the official consolidation.

Coagulation testing sits at the intersection of two Canadian rules and one American section, and the result is a device whose class depends on where it is run. The American section fixes the class for the generic type and expresses it as performance standards. Canada asks first whether the test is run outside a laboratory, and then whether an erroneous result could produce an imminent life-threatening management decision. This article sets out both routes, the neighbouring coagulation sections in each code, and the record a laboratory or point-of-care program should hold.

What is a prothrombin time test in each classification system?

The American identification paragraph fixes both the clinical purpose and the monitors it is used with. Section 864.7750(a) describes a prothrombin time test as a device used as a general screening procedure for the detection of possible clotting factor deficiencies in the extrinsic coagulation pathway, which involves the reaction between coagulation factors III and VII, and to monitor patients receiving coumarin therapy — the administration of one of the coumarin anticoagulants in the treatment of venous thrombosis or pulmonary embolism.

The classification paragraph is a single phrase: Class II, with the class expressed as performance standards. That is a different regulatory shape from special controls. Performance standards are a form of device-specific requirement set out in the code, and they sit on the generic type rather than on a named manufacturer.

Canada does not name the test. It separates the two questions that the American section merges:

• Is the device used outside a laboratory? If so, it is a near patient IVDD, and Part 2 Rule 6 classifies it as Class III.
• If not, how is it used? An IVDD used for patient management is Class II under Part 2 Rule 3, unless the device falls into a listed exception.

One of those exceptions is written for exactly the clinical scenario that a prothrombin time test serves.

How does the prothrombin time class differ between Canada and the United States?

The divergence appears as soon as the setting of use changes.

Item	Canada	United States
Named entry	None; classified as an IVDD	21 CFR 864.7750
Class in a testing laboratory	Class II under the patient-management rules	Class II by performance standards
Class at the point of care or at home	Class III as a near patient IVDD under Part 2 Rule 6	Class II by performance standards
Effect of anticoagulation monitoring	Rule 3(b) can lift the device to Class III where an erroneous result risks an imminent life-threatening management decision	Not a class criterion; the intended use already sits inside the section
Basis for the class	Where the test is run, and the consequence of an error	The generic type of device
Regulatory shape of the class	Class derived by rule	Class expressed as performance standards

The Canadian system therefore produces at least three possible answers for one analyte, and all three are defensible readings of the same schedule:

• A prothrombin time test used inside a laboratory, where an erroneous result would not lead to an imminent life-threatening decision, is Class II under Part 2 Rule 3.
• A prothrombin time test used in the same laboratory where an erroneous result could produce such a decision moves to Class III under Part 2 Rule 3(b).
• A prothrombin time test used at the point of care is a near patient IVDD and is Class III under Part 2 Rule 6, whatever its laboratory counterpart is classed as.

The American classification does not move with the setting. The same performance standard applies to the generic type whether the test is run in a hospital laboratory or on a handheld meter at a clinic counter, and the class stays Class II.

Which coagulation devices sit near the prothrombin time test in each code?

Coagulation involves a reagent, a control and a reader, and the American code names several of them separately.

Device	Canada	United States
Prothrombin time test	IVDD, Class II in a laboratory, Class III at the point of care	864.7750, Class II by performance standards
Thromboplastin and control reagent	IVDD, classified with the test it supports	864.7925, Class II
Partial thromboplastin time reagent	IVDD, classified with the test it supports	864.7925, Class II
Thromboplastin generation test	IVDD	864.7900, Class I
Coagulation factor deficient plasma	IVDD	864.7290, Class II
Automated coagulation analyser	Classified with the IVDDs it runs under Part 2 Rule 7	The higher class of the IVDDs it is used with

Rule 7 of Part 2 is the reason the last row works the way it does. It states that where an IVDD, including its analysers, reagents and software, is intended to be used with another IVDD, the class of both IVDDs is that of the IVDD in the class representing the higher risk. An analyser is therefore pulled up to the class of the highest-risk test it is cleared to run inside the same Canadian framework.

The American code approaches this from the other direction, by naming more of the individual reagent and control generic types and giving each its own section and class.

Do Canada and the United States treat a point-of-care coagulation test the same way?

They do not, and the reason is the same near-patient definition that governs glucose and cholesterol testing.

A handheld INR meter or a clinic-counter coagulation analyser is intended for use outside a laboratory. It is therefore a near patient IVDD in Canada, and Part 2 Rule 6 classifies it as Class III. The Rule 9 table carves out only a few near-patient devices — pregnancy and fertility testing, and cholesterol determination — and coagulation testing is not among them.

In the United States the same meter is a prothrombin time test under 864.7750 and carries Class II by performance standards, regardless of where it is used.

For an anticoagulation clinic that operates both a laboratory analyser and point-of-care meters, the practical consequence is that the same operating procedure can sit behind two different device classes in one Canadian organisation, while the American classification does not change with the setting.

A buyer or quality lead who wants to check a specific product can look it up in the openFDA device classification API or the FDA classification database. On the Canadian side the class follows from the rules, and the rule text is the reference to keep.

What should an anticoagulation testing program keep on file?

Six items, and the first fixes the class.

• The setting of use for each device. Laboratory and point-of-care placements fall under different rules in Canada.
• The maker's intended use statement. The near-patient definition turns on the stated intended use.
• The licence or clearance position. In Canada, the class and licence status; in the United States, the position under the prothrombin time test section.
• The quality control record. Controls, calibration and the interval at which they are run belong with the device file.
• The operator competency record. Where a non-laboratory operator runs the test, the competency record supports the program.
• The result and action log. The record should show what happened when a result fell outside the acceptable range, and which management decision followed.

Which consumables does a testing laboratory restock alongside its coagulation line?

A specimen collection bench restocks containers, pipettes, transport packaging and disposables on the same cycle as its analysers. For practices 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 graduated specimen cups cover sample collection, the laboratory consumables pack with parafilm and pipettes covers bench handling, and programs that also run culture work can start with the sterilization monitoring collection or the biological indicator 5-pack trial.

Sources

1. 21 CFR 864.7750, prothrombin time test
2. 21 CFR 864.7925, thromboplastin and control reagents
3. 21 CFR 864.7900, thromboplastin generation test
4. 21 CFR 864.7290, coagulation factor deficient plasma
5. 21 CFR 864.9, limitations of exemptions
6. Medical Devices Regulations, SOR/98-282, full text and Schedule 1
7. Health Canada, risk-based classification system for in vitro diagnostic devices
8. Health Canada, medical devices
9. openFDA device classification API
10. FDA device classification database
11. CLSI standards
12. ISO 15189:2022, medical laboratories, requirements for quality and competence
13. Public Health Ontario, laboratory test information index
14. Public Health Ontario, infectious diseases
15. College of Medical Laboratory Technologists of Ontario
16. Institute for Quality Management in Healthcare
17. World Health Organization, cardiovascular diseases)
18. Canadian Centre for Occupational Health and Safety, OSH answers
19. US OSHA bloodborne pathogens standard, 1910.1030
20. ISO 6710:2017, single-use containers for venous blood specimen collection

Related reading

• Laboratory Water Baths in Canada vs the US: Which Rules Apply
• Anticoagulation Clinic Orders: What Drives the Cost per INR Test
• Laboratory Glassware in Canada vs the US: Which Standards Apply

CliniEco Medical supplies eye care, laboratory and clinic consumables of the kind described in this article. MDEL #35334. This article is written for laboratory, procurement and infection-control professionals and is not clinical guidance; test selection, quality control and result interpretation belong to the laboratory director and the provincial requirements that apply to the facility.

Frequently Asked Questions

What class is a prothrombin time test in the United States?

Class II, with the class expressed as performance standards under 21 CFR 864.7750. The section describes the test both as a general screening procedure for the extrinsic coagulation pathway and as a device used to monitor patients receiving coumarin therapy.

What class is a prothrombin time test in Canada?

It depends on where the test is run. Inside a testing laboratory the device is classified under the patient-management rules and is Class II unless an exception applies. At the point of care or at home it is a near patient IVDD and is Class III under Part 2 Rule 6 of Schedule 1.

Can a prothrombin time test be Class III in a laboratory?

Yes, in the specific circumstance the rules describe. Part 2 Rule 3 places an IVDD used for patient management in Class II, but moves it to Class III where there is a risk that an erroneous result will lead to a patient management decision resulting in an imminent life-threatening situation for the patient.

Is coagulation testing in the near-patient carve-out list?

No. Part 2 Rule 9 names near-patient devices for the detection of pregnancy or fertility testing and for determining cholesterol level, and places those in Class II. Coagulation testing is not in the table, so the near-patient rule applies unchanged.

What class does an automated coagulation analyser carry in Canada?

It follows the tests it is used with. Part 2 Rule 7 states that where an IVDD, including its analysers, reagents and software, is intended to be used with another IVDD, the class of both is that of the IVDD in the class representing the higher risk.

Do Canada and the United States classify a point-of-care INR meter the same way?

No. The United States places the meter in Class II as a prothrombin time test by performance standards, wherever it is used. Canada classifies a meter intended for use outside a laboratory as a near patient IVDD and places it in Class III.