Independent Lab Accreditation Explained

Every Certificate of Analysis is issued by someone. The analytical results on a COA — the purity percentage, the mass spectrum match, the endotoxin value — are only as credible as the laboratory and the systems behind them. A well-presented document with precise-looking numbers means nothing if the entity that produced it operated without validated methods, without external oversight, and without any accountability structure designed to ensure reproducible results.

This is why the issuing laboratory's accreditation status is not a secondary consideration when evaluating a COA. It is foundational. And the primary international framework for assessing that competence is ISO/IEC 17025.

What ISO/IEC 17025 Is

ISO/IEC 17025, titled "General requirements for the competence of testing and calibration laboratories," is a joint standard published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The current version is ISO/IEC 17025:2017.

The standard specifies what a laboratory must do — and demonstrate — to be considered technically competent to produce valid test results. It covers two broad categories: management requirements and technical requirements. Together these define a quality management system specifically designed for testing and measurement environments.

ISO/IEC 17025 is not the same as ISO 9001, which is a general quality management standard. ISO 9001 addresses whether a process is controlled and consistent; it says nothing specific about whether analytical methods are valid or whether a laboratory's instruments are calibrated correctly. ISO/IEC 17025 goes further: it requires that the methods themselves are fit for purpose and that every element of the testing process — equipment calibration, environmental conditions, analyst competency, sample handling, result reporting — is controlled and documented in a way that can be independently audited.

What Accreditation Requires

Accreditation is the formal process by which an independent national accreditation body assesses a laboratory against ISO/IEC 17025 requirements and declares it competent. The accreditation body itself must be recognised — in most countries, national bodies are members of the International Laboratory Accreditation Cooperation (ILAC) mutual recognition arrangement, which means that accreditation granted in one signatory country is recognised in others.

To achieve and maintain accreditation, a laboratory must satisfy requirements across several domains:

Impartiality and Independence

ISO/IEC 17025:2017 places impartiality at the centre of the standard. The laboratory must identify risks to its impartiality, have top-level commitment to impartiality, and demonstrate that commercial pressure, personnel relationships, or financial incentives do not distort results. An in-house laboratory owned by a product seller faces a structural impartiality challenge that makes accreditation under this section difficult to sustain in practice — the seller has a financial interest in favourable results, and the accreditation body will probe this relationship.

Method Validation

Every test method used by an accredited laboratory must be validated or verified. For standard methods — such as HPLC purity determination under USP general chapter <621> or LAL endotoxin testing under USP <85> — verification confirms that the laboratory can perform the method correctly with its own equipment, reagents, and personnel. For non-standard or laboratory-developed methods, full validation is required: linearity, precision, accuracy, specificity, limit of detection, and limit of quantification must all be established and documented.

This means that when an accredited laboratory reports an HPLC purity result, there is a documented record showing that the method, as run in that laboratory, produces accurate and reproducible results within defined performance parameters. The same is true for LC-MS identity, Karl Fischer water content, and LAL endotoxin.

Equipment Calibration and Maintenance

Every instrument used in testing must be identified, calibrated, and maintained according to a documented schedule. Calibration must be traceable to national or international measurement standards. An HPLC system must be qualified; its detectors, pumps, and column thermostat must perform within specification. A mass spectrometer must be calibrated against reference masses. These are not optional activities — they are documented requirements, and compliance is assessed during accreditation audits.

Personnel Competence

Analysts must be qualified for the tasks they perform. ISO/IEC 17025 requires that laboratories define the competence needed for each function, and that they verify and record that each analyst meets those requirements. This typically includes education and training records, supervised performance evaluations, and ongoing competency monitoring. The result is an audit trail connecting each test result to a qualified, documented analyst.

Measurement Uncertainty

Accredited laboratories must estimate and, where appropriate, report measurement uncertainty for their results. A purity result of 98.3% has an associated uncertainty — perhaps ±0.4% — that reflects the inherent variability of the HPLC method. Accreditation requires that this uncertainty is understood and documented, even if it is not always reported on a COA. This prevents laboratories from reporting spuriously precise numbers that imply a level of accuracy the method cannot support.

Proficiency Testing

Accredited laboratories participate in proficiency testing programmes, where they analyse blind samples provided by an external organiser and their results are compared against those of other participating laboratories. This is the external check on whether a laboratory's methods actually work correctly in practice. Systematic deviations in proficiency tests trigger investigation and, if unresolved, can lead to suspension of accreditation for the affected test type.

Why This Matters for a COA

When a COA is issued by an ISO/IEC 17025-accredited laboratory, each analytical result on that document is backed by:

When a COA is issued by a non-accredited laboratory — or by no independent laboratory at all — none of these assurances apply. The results may be accurate; there is no way to know. The entire value of the certificate rests on nothing verifiable outside the entity that produced it.

The Distinction Between Accredited and Independent

It is important to note that accreditation and independence are related but separate properties. A laboratory can be accredited and yet still not be independent of the seller if the seller owns it or controls it commercially. Conversely, a laboratory can be genuinely independent — a third-party service with no stake in the sale — but not accredited under ISO/IEC 17025.

For a COA to carry full weight, both properties are needed. Independence removes the conflict of interest; accreditation provides the external quality infrastructure. A certificate from an independent non-accredited laboratory is better than a self-issued one, but it still lacks the external assurance that accreditation provides. The strongest position — and the standard against which a verified COA should be assessed — is a certificate from a laboratory that is both independent of the seller and accredited under ISO/IEC 17025.

How to Confirm Accreditation Status

A laboratory that claims ISO/IEC 17025 accreditation should be able to provide its accreditation certificate and its accreditation number. This number can be verified directly through the national accreditation body's online database. In most cases, these databases are publicly searchable without registration.

The verification steps are straightforward:

This process takes a few minutes and can be done for any laboratory claiming accreditation. If a laboratory's accreditation number does not appear in the relevant national database, or if the accreditation is listed as suspended, the claim should be treated as unverified.

What a Scope of Accreditation Tells You

Accreditation is granted for specific tests, methods, and matrices — not as a blanket endorsement of everything a laboratory does. A laboratory may be accredited for HPLC purity determination of peptides but not for LC-MS identity, or accredited for pharmaceutical water testing but not for endotoxin assays. The scope document lists exactly what is covered.

This matters for COA verification because a result generated using a non-accredited method — even by an otherwise accredited laboratory — does not benefit from the accreditation quality assurance. Ideally, the accreditation scope should cover all of the test methods used to generate the results reported on the COA.

Common Misrepresentations to Watch For

Several practices in the industry can create the appearance of accreditation without the substance:

• "ISO-compliant" or "ISO-certified" without accreditation: These phrases often mean the laboratory follows ISO 9001 quality management practices, or that it has self-assessed against some standard. They are not the same as third-party accreditation under ISO/IEC 17025. "Compliant" without a named accreditation body and an accreditation number is an unverifiable claim.
• Expired accreditation: Accreditation must be maintained through periodic re-assessment. A laboratory whose accreditation was granted years ago may have had it suspended or lapsed. The database check must confirm current status, not just historical accreditation.
• Accreditation in one test area used to imply accreditation in another: A laboratory accredited for water testing may display accreditation marks on documents covering HPLC purity determinations that are outside its scope. The scope must be checked against the specific tests reported on the COA.
• Named third-party laboratory with no verifiable accreditation: The laboratory is independent of the seller, which is good, but lacks the external quality infrastructure that accreditation provides. Results should be treated as less robustly assured than those from an accredited laboratory.

Practical Implications for COA Verification

Taken together, the requirements above explain why accreditation status is not merely a formality. A COA from a laboratory without verifiable ISO/IEC 17025 accreditation is a document whose analytical results rest entirely on that laboratory's own internal quality claims — claims that no external body has assessed, validated, or is monitoring on an ongoing basis.

When all of these conditions are met, a COA's analytical results stand on a foundation that an independent body has specifically assessed as competent. When they are not met, the numbers on the document are claims — potentially accurate, but without external verification of the system that produced them.

The verification standard described across this registry — identity by LC-MS, purity by HPLC, water by Karl Fischer, endotoxin by LAL, matched lot number, independent issuer — is most completely realised when the independent issuer holds current ISO/IEC 17025 accreditation covering the methods used. That combination is what the Attestory registry treats as a fully verified COA.

References: ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories; International Laboratory Accreditation Cooperation (ILAC) — mutual recognition arrangements and member body directory; United States Pharmacopeia (USP) — general chapters on analytical methods; WHO good practices for pharmaceutical quality control laboratories. Updated July 2026.