Written and maintained by CASRAI Editorial Board
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Third party inspection is an inspection of goods, usually a shipment or production lot, carried out by an organization that is neither the buyer nor the seller. Buyers of laboratory and medical supplies use it to check the product itself before it ships, which a factory audit does not do. This guide covers general product and supply-chain information only; it is not regulatory, legal or medical advice.
Short answer
A third party inspection checks goods (what was made or shipped), carried out by an independent inspection body. It is different from a factory audit, which approves a site at a point in time, and from incoming inspection, which the buyer performs at receipt. Whether the inspector is itself accredited to ISO/IEC 17020 is a verifiable question, and the accreditation is granted by an accreditation body, not by ILAC.
Definition and scope
In supply-chain use, “third party” means the inspector is independent of both the buyer (first party) and the seller (second party). That reading is an editorial convention used across CASRAI guides; the dictionary entry for second-party audit shows the contrasting case, where a customer audits its own supplier against its own criteria.
The phrase is ambiguous. Search results for it also include building, fire-code and industrial asset inspection, which are a different subject. This page is about inspection of goods being bought, such as consumables, devices and instruments sourced from overseas suppliers.
Pre-shipment inspection: government-mandated versus buyer-hired
“Pre-shipment inspection” (PSI) has a formal meaning in trade law that is narrower than buyer-hired inspection. The WTO Agreement on Preshipment Inspection (checked 3 November 2026) defines preshipment inspection activities as “all activities relating to the verification of the quality, the quantity, the price, including currency exchange rate and financial terms, and/or the customs classification of goods to be exported to the territory of the user Member.” It defines a preshipment inspection entity as “any entity contracted or mandated by a Member to carry out preshipment inspection activities.”
So under the Agreement the party that engages the inspector is a WTO Member government (a “user Member”), not a private buyer. The WTO describes the practice as “employing private companies to check shipment details such as price, quantity and quality of goods ordered overseas.” The Agreement also requires that such activities be conducted in a transparent manner, treats information obtained as business confidential unless it is already public, and sets up independent review procedures (Article 4) for disputes between an exporter and the inspection agency.
A buyer who hires an inspection company to look at a lot before it leaves the supplier is not operating under that Agreement. The same words are used for both, which is why the engagement documents, not the label, should state who commissioned the inspection and what is inspected.
Who accredits an inspection body
ILAC, the International Laboratory Accreditation Cooperation, states in its FAQs (checked 3 November 2026) that it “does not assess and accredit laboratories, inspection bodies, proficiency testing providers or reference material producers.” Accreditation is carried out by accreditation bodies that are signatories of the ILAC arrangement, and ILAC lists ISO/IEC 17020 as the standard those bodies use for the accreditation of inspection bodies. ILAC’s Inspection Committee also publishes questions and answers on how clauses of ISO/IEC 17020 are implemented.
For a buyer, this turns “is the inspector reputable?” into a question that can be checked: which accreditation body accredited this inspection body, to ISO/IEC 17020, and for what scope.
Third party inspection, factory audit and incoming inspection
Three checks are often confused. They examine different things at different moments.
| Check | What it examines | Source |
|---|---|---|
| Preshipment inspection (WTO Agreement) | Quality, quantity, price and customs classification of goods to be exported, by an entity contracted or mandated by a Member | WTO Agreement on Preshipment Inspection, Art. 1 |
| Factory audit | The supplier’s site at a point in time; it does not inspect your shipment | Factory audit guide |
| Incoming inspection | Units drawn and examined from a supplier lot, using a documented sampling plan (for example ANSI/ASQ Z1.4 / ISO 2859-1) | Incoming inspection sampling plan guide |
| Certificate of conformity | A supplier document that accompanies each lot | Certificate of conformity guide |
The factory audit guide says to pair an audit with incoming inspection sampling and to check the certificate of conformity that accompanies each lot. A third party inspection of the lot sits between the supplier’s own paperwork and your receiving dock, and it does not replace either.
Third party inspection and quality inspection in China
“Third party inspection China” and “quality inspection China” are the same practice described from the buyer’s location: an independent body examines goods at or near the supplier before shipment. The WTO and ILAC material cited here does not set country-specific rules, so the questions below apply wherever the supplier is. For imports of medical products into the United States, see CASRAI’s guides on FDA import alerts and Incoterms for the trade terms that accompany a shipment.
Questions to put in an inspection engagement
These follow from the WTO and ILAC points above.
- Who is commissioning the inspection, and is it a buyer engagement or a government-mandated preshipment inspection?
- Which accreditation body accredited the inspection body to ISO/IEC 17020, and what is the scope of that accreditation?
- Is the inspected object the lot or shipment, rather than the factory system (which is the subject of an audit)?
- Which of the supplier’s documents, such as the certificate of conformity, will be compared against the lot?
- Where is the inspection information kept, and who may see it? (The WTO Agreement treats such information as business confidential unless already public; a buyer engagement is governed by its own contract.)
Common misunderstandings
“A third party inspection certifies the factory.”
No. A factory audit approves a site at a point in time; an inspection looks at goods.
“ILAC accredits inspection companies.”
No. ILAC states that it does not accredit inspection bodies; ILAC arrangement signatories do, using ISO/IEC 17020.
“Pre-shipment inspection always means a buyer hiring an inspector.”
Not in the WTO Agreement, where the entity is contracted or mandated by a Member government.
“If an inspector passed the lot, incoming inspection is unnecessary.”
Not on that basis. Incoming inspection is the buyer’s own documented check at receipt, and an inspection report does not replace it.
FAQ
What is third party inspection?
Inspection of goods by a body independent of buyer and seller, commonly before shipment. This page uses that editorial definition; the WTO’s formal preshipment inspection regime is a related but narrower government-led practice.
What is pre-shipment inspection?
Under the WTO Agreement, activities relating to the verification of the quality, quantity, price and customs classification of goods to be exported to a user Member’s territory, performed by an entity contracted or mandated by that Member.
How do I know an inspection body is accredited?
Ask which ILAC arrangement signatory accredited it, to ISO/IEC 17020, and for which scope. ILAC itself does not accredit inspection bodies.
How is it different from a factory audit?
A factory audit approves a site at a point in time and does not inspect your shipment (see the factory audit guide).
Sources
- WTO, Agreement on Preshipment Inspection, Articles 1, 2 and 4 (checked 3 November 2026).
- WTO, Preshipment inspection (checked 3 November 2026).
- ILAC, Frequently asked questions (checked 3 November 2026).
- CASRAI guides: Factory Audit, Incoming Inspection Sampling Plan, Certificate of Conformity.
