Choosing a laboratory is usually treated as a purchasing decision: collect three quotes, compare the totals, pick one. That approach works right up until months later, when a buyer, a marketplace reviewer or a notified body looks at the report and says it is not what they asked for. The tests have been run and paid for by then, and the only fix is to run them again somewhere else.
The better starting point is a different question. Not "which laboratory is best", but "who has to accept this report, and what do they require". Everything else - accreditation, equipment, price - follows from the answer.
Start from who has to accept the report
Before comparing laboratories, be clear about the chain the report has to survive:
- Your customer or distributor, who may forward it to their own auditor or quality department.
- A marketplace compliance team. Amazon's compliance requests, for example, typically ask for test reports from an ISO/IEC 17025 accredited laboratory.
- A notified body, where one has to be involved. For radio equipment, when harmonised standards are not applied - or not applied in full - the Radio Equipment Directive route runs through a notified body, and its assessment will look hard at the testing behind the report.
- Customs or an importer in the destination market, who may ask for documentation during a check.
An acceptor that just needs "a report" and one that needs a report backed by a specific accreditation scope are not shopping for the same thing. Decide which one you are before you compare prices.
Check 1: the accreditation scope, line by line
"ISO/IEC 17025 accredited" on a website says almost nothing by itself. Accreditation under ISO/IEC 17025 - the standard for the competence of testing and calibration laboratories - is granted per test standard and per method. A laboratory can be accredited for emissions testing and not for the immunity clauses of the same product standard, or for one product standard and not the one your buyer named.
So ask for the scope document, or look the laboratory up in its accreditation body's public register, and search for your exact standard number - including the edition. It is a five-minute check, and it prevents the most common version of this problem: a report arrives, the testing was real, but the standard on the buyer's list is not in the laboratory's scope and the report gets set aside.
Two places where the scope question is not negotiable. FCC equipment certification - an FCC ID - has to be supported by testing from a laboratory accredited for the relevant measurement procedures. And marketplace compliance requests increasingly expect accredited reports by default. If your route involves either, verify the scope line before the sample ships, not after.
Check 2: can one laboratory cover the whole configuration?
A typical electronics project is not one test. EMC, product safety, the radio part, battery transport - and for radio products, an RF exposure assessment on top. Some laboratories cover all of it; many cover part of it and partner for the rest.
Splitting the work between laboratories is allowed and sometimes unavoidable. But it has a cost that never shows on the quote: you own the consistency. This lands on real projects. A product's radio tests are done at one laboratory and its EMC and safety at another; the notified body reviewing the file then asks whether the sample that produced the radio results is the same product as the one in the safety report - same hardware version, same firmware. If nobody recorded the configuration on either side, there is no good answer to that question.
One laboratory covering the whole scope is not just a logistics convenience. It puts one team in front of the entire configuration, which is where most of the expensive surprises live.
Check 3: is the report about your product, or a component inside it?
Module and component reports are a legitimate shortcut, and they get misread constantly. A radio module with its own approval does not make the finished product compliant - the module's grant covers the module, in the configuration it was tested in, and the end product still carries its own obligations. This is the same distinction that decides FCC routes, which is covered in more detail in how to tell whether your product needs an FCC ID or falls under SDoC.
A recurring conversation: a customer forwards a component-level report and considers the file closed. The report is not wrong - it just does not describe the product the customer is shipping. When you evaluate a laboratory, ask what they will test at product level and what they will accept from module documentation. A laboratory that never asks about the end product is saving you money today and lending you a problem for later.
Check 4: what you receive at the end
Two laboratories can hand over reports that look identical and behave very differently afterwards. Before committing, ask:
- Do you get the raw measurement data and the test setup photos, or only the report? When an acceptor later asks how the product was configured and terminated - and this happens - the setup photos and data are what answer it.
- Who owns the data, and can the report be re-issued if your company changes name or the original file is lost?
- What happens if the laboratory stops operating? The report itself remains a record of testing that happened, but re-issues, revisions and follow-up testing all need a laboratory that can still speak for the data.
These answers are part of the price even though they never appear on it.
Check 5: how the laboratory handles your configuration
The tested configuration - adapter model, cable lengths, firmware version, accessories, antenna - is what the report describes. A laboratory worth choosing freezes that configuration in writing before testing starts, and wants to hear about changes rather than discover them.
This is also where cheap quotes quietly separate themselves. Two laboratories quote the same product: one assumed a two-wire, double-insulated power configuration; the other asked and confirmed the unit actually has a three-wire input with protective earth. The first quote looks cheaper until the real sample arrives and the scope has to change. A laboratory that asks detailed configuration questions at quotation stage is not being difficult - it is preventing exactly this. The same applies to what is inside the quote in the first place, which is usually why two laboratories quote the same product differently.
Ask one more question while you are at it: what happens if we change the adapter, the antenna or the firmware after testing? The answer tells you how retests will be scoped and priced for the rest of the product's life, not just for this project.
Check 6: is there an engineer you can actually talk to?
Testing takes days or weeks, and things drift. A measurement sits too close to the limit line. A sample behaves differently from the quote's assumption. A document turns out to be a draft. The difference between a tolerable project and a painful one is usually whether the laboratory picks up the phone when that happens - or sends a finished report three weeks later with a FAIL in it.
Before committing, find out who your technical contact is and whether you can ask questions during testing, not just receive documents at the end. This is hard to verify from a website, which is exactly why it belongs on the checklist rather than in the contract's fine print.
The checklist, in one table
| Ask | A weak answer | A strong answer |
|---|---|---|
| Accreditation scope for my exact standard | "We are ISO 17025 accredited" | Scope document or register entry showing your standard number and edition |
| Who has to accept the report | "It's a CE report, everyone accepts it" | A discussion of your acceptor's requirements before quoting |
| Coverage of the full configuration | Quotes only the tests the laboratory happens to run | Names what it does not cover and how that gap is handled |
| The tested configuration | Not mentioned until the report | Frozen in writing: adapter, cables, firmware, accessories |
| A change after testing | "We would have to look at it" | A defined retest / change-assessment path with pricing rules |
| Deliverables | The report PDF | Report + raw data + setup photos + configuration description |
Where price fits in
None of this means the cheapest quote is the wrong one. It means the cheapest quote with an unspecified scope is the expensive one. Put the scope next to the price: which tests are included, what is excluded, what triggers extra charges, and what arrives at the end. A low price is perfectly reasonable when the scope behind it is explicit. It is a problem only when it is not.
How we put this into practice
We ask for the same four things before quoting that this article asks you to check: what the product is, whether it transmits radio, how it is powered, and - just as important - who has to accept the report. Then we confirm which standards apply, which of them sit inside our accreditation scope, and which parts, if any, we would handle with a partner laboratory.
It also means the checks in this article - scope lines, the frozen configuration, the deliverables list - are things we answer in writing as part of the quotation, not things you have to dig out of us after the sample arrives.
SZC-LAB runs EMC, RF and SAR testing and the certification programmes around them (CCC, CE, FCC, UL, RCM, KC, BQB and others) as one project, so the configuration is tested as a whole rather than assembled from separate files. Where part of the scope is not ours, we say so at quotation stage rather than after the sample has shipped - that is also what our project approach page describes in detail.
If you are comparing laboratories right now, send us the product, the target market, and anything your buyer or marketplace has already asked for in writing.
We will come back with which standards apply, whether they sit inside our accreditation scope, and what the test programme would look like - so you can compare laboratories on scope instead of totals, and know about any gap before the sample ships rather than after.
Send your product and target market for a scope confirmation