Choosing an Independent Analytical Laboratory: Scope, Methods, Reporting and the 2026 Landscape

Choose a laboratory by four things, in this order: whether the specific methods you need sit inside its accreditation scope, or whether it says plainly that they do not; whether it analyses peptides routinely; whether its report names the method and states uncertainty; and whether it is independent of the party whose material you are testing. A logo that says 'accredited' answers none of these by itself, because accreditation is granted for a listed set of tests, not for a building.

This page is about choosing a laboratory. What the labels ISO/IEC 17025, ISO 9001 and GMP each certify is decoded in a separate article in this cluster, and is assumed here. The last section sets out what six laboratories active in this market say about themselves, checked on each laboratory's own website on 15 September 2026. It is a snapshot, listed in no order, and inclusion is not a recommendation.

Why 'accredited' alone is not an answer

ISO/IEC 17025 accreditation is an assessment of a laboratory's competence to perform specific activities, and the accreditation body issues a scope listing exactly which tests, on which materials, by which methods, are covered ^[1]. Accreditation bodies are themselves assessed under ISO/IEC 17011 ^[2], and those that are signatories to the ILAC Mutual Recognition Arrangement recognise each other's accreditations, which is what lets a result from one country be relied on in another ^[3]. None of that extends to tests outside the scope. A laboratory accredited for heavy metals in plant material is not thereby accredited for peptide purity by HPLC.

The check takes minutes. Take the accreditation body and certificate number the laboratory quotes, open that body's public directory, and read the scope document for the methods you intend to order; in the United States, A2LA's directory lets you look up a certificate number and view its scope ^[4]. If the laboratory does not quote a certificate number, ask for one. If the method you need is not on the scope, the result may still be competent work, but it is not accredited work, and your records should say so.

Does the laboratory run peptides routinely?

Synthetic peptides carry impurities that are close chemical relatives of the target — deletion sequences, truncations, oxidised and deamidated forms — and separating them from the main peak is the whole difficulty. A laboratory that analyses peptides every week has columns, gradients and integration rules tuned for that problem. A general chemistry laboratory that accepts the occasional peptide sample may run a generic method that merges those relatives into the main peak and reports a flattering figure. Validation guidance puts specificity first for exactly this reason: a method must be shown to distinguish the analyte from what is likely to be present with it ^[5].

Ask how many peptide samples the laboratory runs in a typical month, whether it holds reference standards for the sequences it tests, and whether it runs a system suitability check before each sequence of injections. A laboratory that answers those questions easily is doing the work you are paying for. If the terms are unfamiliar, the handbook page on system suitability checks and reference standards explains what a good answer sounds like.

Methods to ask for by name

Reporting format and stated uncertainty

ISO/IEC 17025 sets out what a test report must carry: identification of the item, dates of receipt and analysis, the method used, and a statement that results relate only to the items tested; where relevant to interpreting a result, it also expects measurement uncertainty to be reported ^[1]. A purity figure with its uncertainty lets you tell whether two results genuinely differ, which a bare percentage cannot ^[6]. Ask to see a redacted sample report before ordering. A report showing the chromatogram, the integration and the method conditions is worth more than one that prints a single number under a logo.

Independence and conflicts of interest

A laboratory is independent in the sense that matters here when it reports to you, you chose the container it analysed, and it has no commercial interest in the result. Many laboratories in this market earn most of their income from suppliers testing their own stock, which is legitimate work but means the supplier chose the sample. When you commission a test yourself that conflict disappears, whichever laboratory you use. Ask whether the laboratory sells, distributes or is owned by a seller of the materials it tests; the answer should be a plain no.

Questions to ask before sending anything

1. Which accreditation body and certificate number, and are the methods I am ordering on the scope ^[4]?
2. How often do you analyse peptides, and do you hold reference standards for this sequence ^[5]?
3. Which method, column, gradient and wavelength will be used, and will the chromatogram be in the report?
4. Will the report state measurement uncertainty ^[6]?
5. How much material does each test consume, and do you need unopened containers?
6. What are your intake requirements, and can you accept this material from where I am sending it?
7. Can the report be confirmed with you directly by a third party, and how?

The 2026 landscape, as each laboratory states it

The following reflects each laboratory's own website as read on 15 September 2026. Accreditation status is given as the laboratory states it, not as any third party characterises it, and where a laboratory's pages make no accreditation claim, that is what is recorded. Janoshik describes itself as an independent testing laboratory and says every report in its database is verifiable through its Verify tab or the QR code on the report; its about page makes no accreditation claim ^[7]. Testides describes itself as an independent analytical data service, states that 'the laboratory performs the measurement' while Testides manages coordination, data review and reporting, and says that 'accreditation remains facility, method, and scope specific' and that, where applicable, testing is conducted within the scope of ISO/IEC 17025 accreditation ^[8]. MZ Biolabs, in Tucson, Arizona, states a DEA licence and lists QTOF mass spectrometry, linear ion trap and HPLC among its instruments; its pages make no ISO/IEC 17025 claim ^[9].

Freedom Diagnostics, in Franklin, Tennessee, established in 2023, states that every certificate includes both HPLC purity and LC-MS identity, and that certificates are searchable by accession number or company name; its home page makes no accreditation claim ^[10]. Chromate states that it is US-based, that its tests are by HPLC unless otherwise specified, that LC-MS is offered as a qualitative test, and that endotoxin is measured by kinetic chromogenic LAL; results are released through a Verify portal, and the service pages make no accreditation claim ^[11]. ACS Laboratory, in Sun City Center, Florida, states that it is 'ISO/IEC 17025:2017 Accredited by A2LA' ^[12], and its peptide pages list HPLC, LC-MS and Karl Fischer among the methods offered ^[13]. Before relying on that accreditation for a peptide result, check the A2LA scope for the specific method ^[4].

Two cautions about the lookup column. A report lookup confirms that a document was issued and has not been altered; it does not confirm that the container you hold is the one tested, a distinction worked through in confirming a report with the laboratory that issued it. And a code printed on a certificate is only as good as the page it opens, which is what a QR code on a certificate can and cannot prove. When you commission the test yourself, both concerns shrink: the report is addressed to you and the sample was yours.

Websites change and accreditations are granted, extended and withdrawn. Re-read the laboratory's own statement and the accreditation body's directory on the day you order ^[4], and record what each said, with the date, alongside the result. That record, not this table, is what later readers of your work will need ^[1].