Quick facts
- An occult blood test is a Class II entry in the United States at 21 CFR 864.6550 under product codes such as KHE for an occult blood reagent and GGG for a guaiac reagent.
- Canada classifies an occult blood test as an in vitro diagnostic device. Used in diagnosis or patient management it is Class II under Rule 4 of the Medical Devices Regulations.
- A test whose intended use is the screening for or diagnosis of cancer is lifted to Class III by Rule 4(a) — a genuine class difference between the two countries.
- The class therefore follows the intended use statement, not the reagent. The same guaiac chemistry is Class II in the United States and can be Class III in Canada once it claims cancer screening.
- A test intended for patient management rather than diagnosis takes a different route again, under Rule 3.
- The regulation text quoted here is current to 2026-09-21 and was last amended on 2026-06-17.
An occult blood test looks for blood that is present in such small quantities that the eye cannot see it. The classic format is a guaiac card that turns blue when a faecal sample carries haem, and the classic use is colorectal cancer screening. The test itself is simple; the class in Canada turns on the sentence the manufacturer writes as the intended use.
What is an occult blood test?
The United States describes the test in its own words. Under 21 CFR 864.6550, an occult blood test is a device used to detect occult blood in urine or feces, and the rule adds that occult blood is blood present in such small quantities that it can be detected only by chemical tests of suspected material, or by microscopic or spectroscopic examination.
Two things in that sentence matter. The test covers both urine and faeces, so it is one entry serving two clinical uses. And the object is the detection of hidden blood, not the diagnosis of a named disease. A test sold to find hidden blood is described one way; a test sold to screen for colorectal cancer is described another way, and the Canadian rules separate the two.
How do Canada and the United States classify an occult blood test?
The test is Class II in the United States. In Canada the class depends on the intended use.
| Item | Canada | United States |
|---|---|---|
| Occult blood test used in diagnosis | Class II by Rule 4 | Class II, 21 CFR 864.6550 |
| Test whose use is screening for or diagnosis of cancer | Class III by Rule 4(a) | Still the same named entry |
| Test used for patient management | Class II by Rule 3 | Still the same named entry |
| Basis named in the rulebook | The intended use statement | The named entry and its controls |
| What decides the class | Whether cancer screening is claimed | Which entry the product is filed under |
| Result of the difference | A higher licence tier where cancer is claimed | A Class II entry with special controls |
In the United States the test is a single Class II entry with special controls. In Canada the test is an in vitro diagnostic device, and Part 2 of Schedule 1 applies. Rule 4 puts an in vitro diagnostic device used in diagnosis or patient management in Class II unless it falls into a listed category, and the first category is a device intended to be used in screening for or in the diagnosis of cancer. That category lifts the device to Class III.
That is the difference in one line. The same card and the same reagent sit in Class II if the intended use is the detection of occult blood, and in Class III if the intended use is colorectal cancer screening.
Why does the intended use decide the class in Canada?
Because the Regulations classify an in vitro diagnostic device by what it is for, and a screening claim for cancer is a named trigger for the higher class.
Rule 4 states that a device not caught by the earlier transmissible-agent rules, and intended to be used in diagnosis or patient management, is Class II unless it is intended to be used in screening for or in the diagnosis of cancer, in which case it is Class III. The list of triggers also includes genetic testing, screening for congenital disorders in the fetus, disease staging, and any case where an erroneous result would cause death or severe disability. A faecal occult blood test used in a colorectal screening programme meets the first trigger directly.
The design rule is easy to state: read the intended use, then read the trigger list. A test described as detecting occult blood stays at Class II; a test described as screening for bowel cancer moves to Class III. Two products that share a reagent can sit in different classes.
Which licence and records differ between Canada and the United States?
For a supplier the class is not a label; it decides which paperwork has to exist before the test can be sold.
In the United States the occult blood test is a Class II entry with special controls, and it reaches the market through premarket notification under section 510(k) unless the entry is specifically exempt; a control intended for use with the test is exempt subject to section 864.9. In Canada a Class II or higher in vitro diagnostic device needs a medical device licence before sale under section 32 of the Regulations, and a licence application is supported by a quality-system certificate against ISO 13485, together with the labelling and evidence the Regulations set out. A test that claims cancer screening needs the Class III licence and the supporting evidence that class attracts. A supplier that treats a screening test as an ordinary diagnostic reagent is holding a Class III device with a Class II file.
What do the two rulebooks actually say?
The two texts are short, and the difference between them is the whole point of this article.
| Rule or entry | Verbatim wording | Effect on an occult blood test |
|---|---|---|
| Rule 4, Canada | IVDD … intended to be used in diagnosis or patient management is classified as Class II | Class II for a general detection claim |
| Rule 4(a), Canada | it is intended to be used in screening for or in the diagnosis of cancer | Class III for a colorectal screening claim |
| Rule 3, Canada | An IVDD that is intended to be used for patient management is classified as Class II | Class II for a management claim |
| Rule 8, Canada | If rules 1 to 7 do not apply, all other IVDDs are classified as Class I | A bare reagent with no clinical claim |
| 21 CFR 864.6550, US | Occult blood test | Named Class II entry, product code KHE |
Read together, the five lines explain why a supplier cannot move the class by relabelling. A screening test described as a general reagent, while its label claims bowel cancer screening, is described against the text, not against the product.
Which consumables does a faecal or urine collection point restock?
A clinic that runs occult blood testing runs on the same supplies as any other collection point. The graduated 90 mL specimen cups carry the sample to the bench, and where the card travels to a laboratory the 3-wall specimen transport bags hold the primary receptacle with the paperwork. A clinic that also holds a spore test line pairs the sterilization monitoring collection with the 24-hour monitoring five-pack trial. Clinics and multi-site groups ordering at case level use the wholesale ordering page, and the B2B wholesale collection lists the lines held for institutional buyers. Reselling? become a distributor.
Sources
- 21 CFR 864.6550, Occult blood test
- 21 CFR 864.6550, Fecal occult blood control
- 21 CFR 864.3250, Specimen transport and storage container
- 21 CFR 864.6160, Manual blood cell counting device
- Medical Devices Regulations, SOR/98-282, full text
- openFDA device classification API
- ISO 15189:2022, medical laboratories, requirements for quality and competence
- ISO 13485:2016, medical devices quality management
- ISO 14971:2019, risk management for medical devices
- CLSI, clinical and laboratory standards
- Public Health Ontario, laboratory services test index
- CCOHS, OSH answers
- Government of Canada, medical devices guidance
- Standards Council of Canada
- Canadian Dental Association
- Royal College of Dental Surgeons of Ontario
- College of Optometrists of Ontario, standards of practice
- Opto, eye health library
- American Academy of Ophthalmology, eye health
- 21 CFR 864.7500, Whole blood hemoglobin assays
A screening result that is not written down is a screening result that cannot be repeated. The printable specimen receipt and rejection log is a blank sheet with columns for the patient, the specimen, the time received and the accept or reject, so a delay or a shortfall is visible on the day. The receipt log generator on the same page sizes the sheet to the number of collection points a site runs. No account and no sign-up are needed to open either one.
Every collection point is organised differently. Ask a compliance specialist and you will get a written answer specific to your equipment and province, with the regulation or standard it is based on cited.
Related reading
- Stool Sample Collection in Canada vs the US: Which Packaging Rules?
- Stool Collection Kits: What the Clinic Gives and What the Lab Accepts
- Blood Culture Bottles in Canada vs the US: Which Rules Apply?
CliniEco Medical supplies eye care, laboratory and dental consumables of the kind described in this article. MDEL #35334. This article is written for optometry, laboratory and procurement professionals and is not legal advice; the class of a device and the records kept by a clinic belong to the manufacturer and to the requirements that apply to it.
Frequently Asked Questions
Is an occult blood test a Class II device in the United States?
Yes. An occult blood test is a Class II entry at 21 CFR 864.6550, with product codes such as KHE for an occult blood reagent and GGG for a guaiac reagent.
How does Canada classify the same test?
In Canada an occult blood test is an in vitro diagnostic device. Used in diagnosis it is Class II under Rule 4. If its intended use is the screening for or diagnosis of cancer, Rule 4(a) lifts it to Class III.
Does the same card really get two classes in Canada?
Yes, and the difference is the intended use statement. A test sold to detect occult blood is Class II; the same chemistry sold for colorectal cancer screening is Class III.
Which category does cancer screening fall under?
Rule 4(a), one of the categories that lifts an in vitro diagnostic device from Class II to Class III. The other categories include genetic testing, screening for congenital disorders in the fetus, and disease staging.
What does the class change for a supplier?
Both classes need a medical device licence under section 32 in Canada, but a Class III licence attracts more supporting evidence than a Class II one. In the United States the entry is Class II with special controls.
Can an occult blood test be Class I in Canada?
Only if it is a bare reagent with no clinical claim that meets rules 1 to 7, which would leave Rule 8 to place it in Class I. Once a diagnostic claim is made, Rule 4 applies.
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