What is an in vitro diagnostic (IVD)? Meaning and examples

What is an in vitro diagnostic (IVD)?

An in vitro diagnostic (IVD) examines a human specimen outside the body to give health information. A urine pregnancy test and a blood glucose meter with test strips are both IVDs.

IVD is the standard medical abbreviation for in vitro diagnostic. "In vitro" describes where the specimen is examined, not a rule that the test must run in a laboratory. The US Food and Drug Administration (FDA) says some tests are used in laboratories or other health professional settings, and other tests are for consumers to use at home. A home test can be an IVD just as much as a hospital analyzer.

In vitro diagnostic meaning in US regulation

The US definition sits in 21 CFR 809.3(a). It covers reagents, instruments and systems intended for use in the diagnosis of disease or other conditions, including a determination of the state of health. They are also intended for the collection, preparation and examination of specimens taken from the human body, so an IVD isn't only the disposable kit. The instrument that reads the sample, and the reagents it runs, can be in vitro diagnostic medical devices too. Treat this US text as one jurisdiction's definition, not a global rule.

Examples of in vitro diagnostic tests

• A urine pregnancy test detects human chorionic gonadotropin (hCG) in a urine sample.
• A blood glucose system uses a meter and test strips with a small blood sample to measure sugar levels.
• Influenza diagnostic tests include antigen tests and nucleic acid tests run on specimens from the patient.

Not every glucose monitoring product examines a removed specimen. Check how that device works before you call it an IVD.

How IVDs differ from other medical devices

An ordinary X-ray, MRI, or ultrasound examination images the patient rather than testing a removed specimen, so it isn't an IVD examination. A test-tube experiment isn't automatically diagnostic, either. The US definition requires an intended diagnostic purpose involving human specimens.

What "for in vitro diagnostic use only" means

On a reagent or kit, "for in vitro diagnostic use" means the product is for diagnostic testing of a human specimen outside the body. It isn't permission to administer the reagent to a patient. In the US, 21 CFR 809.10(a)(4) asks for the statement "For In Vitro Diagnostic Use" and any other limiting statements appropriate to the intended use, subject to the section's applicability provisions and exceptions. That required statement does not include the word "only", even though labels and searches keep adding it.

But those words on their own don't prove much. They aren't evidence that the FDA cleared or approved the product, and they don't mean the test works on every specimen type or suits home use. Those answers sit in the intended use, limitations and instructions that the same section requires, so read those parts of the label.

Don't confuse that label with research use only (RUO) labeling. Under 809.10(c)(2)(i), a product in the laboratory research phase of development that is not represented as an effective in vitro diagnostic product must carry "For Research Use Only. Not for use in diagnostic procedures." The two labels aren't interchangeable.

IVD medical devices in India

In India, the Central Drugs Standard Control Organisation (CDSCO) regulates IVDs under the Drugs and Cosmetics framework and the Medical Devices Rules, 2017. CDSCO classifies IVDs by risk, using Part II of the First Schedule to those Rules:

A risk class is not a licence. A device type's entry in a classification list doesn't prove that a particular manufacturer's product is approved. Check CDSCO's separate classification and licensing information before you treat a list entry as approval.

RegAffairs AI has a source-linked conversation about IVD meaning, diagnostic-use labels and India's risk classes.