The Medical Device Definition in GN-00 and How to Apply It

1. Key takeaways

Whether a product is a medical device is the first fork in every compliance pathway. The definition sits in guidance notes GN-00, Guidance Notes on Definitions and Abbreviations in the Medical Device Administrative Control System, in a Chinese version updated on 2 October 2025. MDD provides 3 online tools to support the judgement: one asking whether a product is a medical device, a general medical device classification programme, and an in vitro diagnostic medical device classification programme. An error at this stage propagates downward: wrong class, wrong pathway, wrong documents, and the eventual outcome is a returned application or a tender finding of non-conformity.

Because the determination is rarely contested in writing, it tends to be made informally and then relied on for years. That is the weakness in most files. A written, dated determination with the reasoning attached costs little and answers the first question any purchaser, distributor or inspector will ask.

The GRZAN view. The definition is decided by the claim and the mode of action, so marketing language written for commercial reasons can change the regulatory status of the product.

2. Legal basis

Definition, scope and adjacent regimes. GN-00 contains the definition of a medical device and the abbreviations used throughout MDACS. GN-01, current version updated and issued on 1 September 2026, lists at paragraph 3.2.1 products that meet the definition but fall outside the existing MDACS scope. TR-010, on combination products, sets the principles for determining the attribute of products that combine a device with a medicinal or biological component. The Pharmacy and Poisons Ordinance (Cap. 138) supplies the definition of a pharmaceutical product, which is the boundary most often tested. The MDACS scheme page carries the entry points to the online tools.

The tools are aids, not decisions. Each tool produces an output that can be saved, and that output is useful precisely because it records what was asked and what was answered. It does not replace the definition in GN-00, and a determination that contradicts the tool should say so and explain why.

3. Expert insights

The definition turns on intended use and mode of action. Two questions decide the attribute: what the manufacturer claims the product is for, and by what principal means it achieves that purpose. Products acting mainly by pharmacological, immunological or metabolic means normally fall within the pharmaceutical product definition; products acting mainly by physical means are devices. The second question is the one companies skip, and it is the one that separates an antiseptic claim from a barrier claim on otherwise similar products.

Meeting the definition and being in scope are separate questions. Paragraph 3.2.1 of GN-01 lists products that satisfy the device definition but are not covered by the existing MDACS scope. A product can therefore be a medical device and still be unable to obtain a listing. The two judgements have to be made in sequence and recorded separately, because collapsing them produces a file that argues the wrong point at length.

Combination products are routed by principal mode of action. TR-010 addresses drug-device combinations, biological-device combinations and similar forms. For these, the principal mode of action is determined first, and only then does the product take either the pharmaceutical route or the device route. Submitting both files in parallel is a common response to uncertainty and it is the wrong one, because each authority will ask why the other file exists.

Tool output can be used for external proof. A saved screenshot of the tool result, kept with the determination note, supports the statement that the product was assessed against the official position. This is a practical estimate of what purchasers accept, not a formal evidential rule.

4. Practical recommendations

• Freeze the claims before the determination. Settle the intended use wording in the instructions and promotional material first, then start the attribute assessment against that fixed text.
• Keep the three-layer order fixed. Determine whether the product is a medical device, then whether it falls within MDACS scope, then whether it is a GMD or an IVDMD and at which class.
• Seek written confirmation for borderline products. Where the Cap. 138 boundary is in play, put the question in writing to the Pharmacy and Poisons Board or to MDD and keep the reply.
• Conclude the attribute before project approval. For combination products, do not commit to document preparation until the principal mode of action is settled, since the pathway decision follows it.
• Reassess when the claim changes. A new indication, a new population or a new performance claim can move a product across the device boundary, and the earlier determination then becomes a liability.

5. Verification checklist

• □ Attribute determination completed under GN-00 and recorded in writing.
• □ Online tool on whether a product is a medical device used and output retained.
• □ Product checked against paragraph 3.2.1 of GN-01 for MDACS scope.
• □ Principal mode of action of any combination product determined under TR-010.
• □ Intended use claims consistent across all outward-facing material.
• □ Written responses on borderline products archived.

Regulatory information verified as at 29 October 2026 against the official sources listed under legal basis; where those sources are updated, the latest published version prevails.

How GRZAN can help. GRZAN provides medical device and IVD registration, quality system, authorised representative and local testing support for Hong Kong, China. Our team manages Medical Device Administrative Control System (MDACS) listings, coordinates import licensing, and supports post-market vigilance obligations. Business enquiries: info@grzanglobal.com