Most guides to Certificates of Analysis tell you to look for a third-party laboratory and, ideally, one accredited to ISO/IEC 17025. That advice is sound, but it is rarely explained. What does the accreditation actually certify? What can it not tell you? And how do you check it? This article answers those questions and ends with a verification checklist that can be applied to any COA. For how to read the numbers on a COA, start with our COA reading guide and our HPLC and mass spectrometry explainer.
What ISO/IEC 17025 Is
ISO/IEC 17025:2017 ("General requirements for the competence of testing and calibration laboratories") is the international standard against which analytical laboratories are assessed. It is organized around five groups of requirements: general (impartiality and confidentiality), structural, resource (personnel, equipment, metrological traceability), process (methods, sampling, handling of test items, measurement uncertainty, reporting), and management system. An independent accreditation body assesses the lab against the standard; accreditation bodies that are signatories to the ILAC Mutual Recognition Arrangement, such as A2LA, ANAB and UKAS, have their accreditations recognized internationally.
What Accreditation Does Indicate
- Documented, validated methods. Methods used within the accredited scope must be validated or verified for the intended use.
- Traceable measurements. Balances, pipettes and instruments are calibrated against traceable references.
- Personnel competence. Analysts are trained and their competence is monitored.
- Impartiality. The lab must identify and manage conflicts of interest, which is directly relevant when the customer is also the seller.
- Reporting rules. Reports must include required elements such as unique identification, the sample description, the method used, and the date, and changes to reports are controlled.
- Ongoing surveillance. Accredited labs are reassessed periodically, typically with proficiency testing or interlaboratory comparisons.
What Accreditation Does Not Indicate
- It is scope-specific. A lab may be accredited for some tests and not for others. Accreditation for, say, metals analysis does not cover peptide HPLC. The accreditation certificate lists a scope of tests, and the report should state whether the specific test is within it.
- It is not a product certification. It speaks to the competence of the lab, not the quality or safety of the material tested.
- It is not GMP. Good Manufacturing Practice concerns how a product is made; ISO/IEC 17025 concerns how a lab tests. They are different frameworks, and ISO 9001 (a general quality-management standard) is different again.
- It does not validate what was submitted. A lab tests the sample it receives. If the submitted sample was not representative of the lot, the report cannot reveal that.
The Method Layer: What "Validated" Means
For chromatographic purity methods, validation follows the framework in ICH Q2(R2), which describes performance characteristics such as specificity, accuracy, precision, linearity, range, and detection and quantitation limits. Within a run, system suitability checks (for example, resolution between peaks, peak tailing, and injection repeatability) show that the instrument was performing adequately that day. General chromatographic requirements are described in USP General Chapter <621>. A COA that states the method (column type, mobile phase, wavelength, gradient) lets a reader judge whether it is a recognizable peptide-RP-HPLC method; one that states only a percentage does not.
Purity Is Not the Whole Story
HPLC purity by peak area reports the proportion of detected UV-absorbing material that is the main peak. It does not report how much of the vial's mass is peptide, as opposed to water, counter-ions such as trifluoroacetate, and salts. The two measures answer different questions, and a high area-percent purity is compatible with a mass that is substantially non-peptide. Identity is established separately, by mass spectrometry.
Data Integrity
Regulators evaluate analytical data against the ALCOA+ principles (attributable, legible, contemporaneous, original, accurate, plus complete, consistent, enduring and available), laid out in FDA's data-integrity guidance for current good manufacturing practice. For a COA reader, the practical implication is that the chromatogram and spectrum shown should be traceable to a raw data file with a date, instrument and analyst, and should not be a cropped image of unknown origin.
A Verification Checklist
- Does the report name the laboratory, with a physical address and contact?
- Is the lab independent of the manufacturer and seller?
- Does the lab publish an accreditation certificate, and does its scope list the specific type of test?
- Check the accreditation body's public directory to confirm the certificate is current.
- Does the report carry a unique report number, the batch or lot number, and a test date?
- Is the method identified, and are chromatogram and mass spectrum included in full?
- Is identity confirmed by MS and not only purity by HPLC?
- Is there an authorized signatory?
- Does the batch on the report match the batch on your vial?
- Will the lab or seller confirm the report on request?
Sources
- ISO/IEC 17025:2017. General requirements for the competence of testing and calibration laboratories.
- ILAC. Mutual Recognition Arrangement (ILAC-MRA) and list of signatory accreditation bodies.
- ICH Q2(R2). Validation of Analytical Procedures (2023).
- United States Pharmacopeia. General Chapter <621> Chromatography.
- U.S. Food and Drug Administration. Data Integrity and Compliance With Drug CGMP: Questions and Answers — Guidance for Industry (2018).
For research use only. Not for human or veterinary consumption. This article is educational and describes published literature and standards; it makes no claims about the use of any product.