You asked your supplier for test reports. Twelve pages arrived, in a layout you have not seen before, with columns of numbers and a conclusion you are not sure how to read.
The instinct is to check whether it says “pass”. Most reports do not say that. And a report that does say it is only passing against somebody’s specification — which may not be yours.
Here is how to read one properly.
What a Test Report Is — and What It Is Not
A test report is a record of specific tests performed on a specific sample, submitted on a specific date, by a specific laboratory.
It is not:
- A certification of ongoing production. It describes the sample tested, not the goods you will receive.
- Transferable. A report for one fabric does not cover a different composition, weight or colour, even from the same mill.
- A pass/fail judgement on your behalf. The laboratory reports numbers. The acceptance limit comes from you or from your market’s regulation.
- A substitute for a specification. If you did not write a limit, nobody was measuring against one.
That last point is where most confusion lives. Read the “requirement” or “specification” column on any report. If it is blank, or says “no requirement specified”, the report is telling you a number, not an answer.
The Anatomy of a Report
| Field | What it tells you | What to check |
|---|---|---|
| Report number and date | Identity and age of the test | Is the date before or after the production run it is meant to cover? |
| Client / applicant | Who commissioned the test | Is it your supplier, or a third party you cannot trace? |
| Sample description | Composition, weight, colour, structure | Does it match the fabric on your order — not a similar one? |
| Test method | The standard followed, e.g. ISO 6330 or AATCC 135 | Different methods give different numbers. Compare like with like only. |
| Test conditions | Temperature, cycle, number of washes, drying method | A result without conditions cannot be interpreted |
| Result and unit | The measured value | % change, grey scale grade, mg/kg — the unit tells you how to read it |
| Requirement / limit | The pass mark, if one was supplied | Blank means no judgement was made |
| Conclusion / remark | The laboratory’s summary | Often narrower than buyers assume |
The Tests That Matter for Sleepwear
| Property | Common methods | Reported as | Why it matters to you |
|---|---|---|---|
| Fibre composition | ISO 1833 / AATCC 20 | % by fibre | Supports your label claim; a mismatch is a compliance issue, not a quality issue |
| Dimensional stability (shrinkage) | ISO 6330 + ISO 5077 / AATCC 135 | % change in length and width | Determines fit after the first wash — the single most common consumer complaint |
| Colourfastness to washing | ISO 105-C06 / AATCC 61 | Grey scale grade | Bleeding onto other garments, and onto itself |
| Colourfastness to rubbing (crocking) | ISO 105-X12 / AATCC 8 | Grey scale grade | Transfer to skin and to lighter fabrics |
| Colourfastness to perspiration | ISO 105-E04 | Grey scale grade | Relevant for anything worn against skin overnight |
| Pilling | ISO 12945-2 (Martindale) / ISO 12945-1 (pilling box) | Grade | Appearance after weeks of wear and washing |
| Abrasion resistance | ISO 12947 (Martindale) | Cycles to end point | Longevity, especially on cuffs and seats |
| pH value | ISO 3071 | pH | Skin compatibility; also an OEKO-TEX parameter |
| Formaldehyde | ISO 14184 | mg/kg | Regulated residue, tighter limits for children’s products |
| Extractable heavy metals / azo colorants | ISO 17234 / EN 16711 series | mg/kg | Restricted substances for OEKO-TEX and REACH |
You will not need every one of these on every fabric. What matters is that the tests you do require are named in your tech pack with the method, because the method is the specification.
Method Plus Condition Beats the Number
“The fabric shrinks 2%.” That sentence means nothing on its own.
Two percent after how many wash cycles, at what temperature, in what wash programme, and dried how? One wash at 30°C line dried is a different test from five washes at 40°C tumble dried, and produces a very different number on the same fabric.
This is why buyers who compare a report from one mill against a report from another get nowhere. If the methods differ, the numbers are not comparable — and neither is the decision you make from them.
The rule: never accept a shrinkage or fastness figure without the method reference and the test conditions printed next to it.
Pass or Fail Is Your Spec, Not the Lab’s
A laboratory’s job is to measure accurately and report what it did. It does not know your target market, your price point or your returns data.
So the pass mark has to come from somewhere else:
- Regulation, where one exists — restricted substances, children’s flammability, labelling.
- Your own specification, written into the tech pack — for example, shrinkage within a stated range after a stated wash programme.
- Your retailer’s requirement, if you are supplying a store with its own standards.
If none of those three exists, the report is informational only. It is still useful — it lets you compare lots and spot drift — but it will not protect you in a quality dispute, because there was no agreed standard to fall below.
Five Ways Reports Get Misread
| Misreading | What goes wrong |
|---|---|
| Accepting a report for a different fabric | Same mill, different composition, weight or colour — the report does not transfer |
| Comparing numbers from different methods | A 1% and a 3% shrinkage figure may both be correct and not comparable |
| Treating one passing lot as permanent | Each lot is a separate dyeing and finishing run; one pass is one data point |
| Using a report older than the fabric | A report issued before a fibre or finish change describes a different material |
| Assuming trims were tested | Thread, elastic, drawcord and labels are separate inputs and are frequently excluded |
The fifth one catches people most often. A garment can fail at retail on a component that was never in scope.
What to Ask Your Supplier For
- Which tests, and against which named methods?
- Which sample was tested — composition, weight, colour, finish?
- Per colour or per lot, or one report for the whole program?
- Is the report issued in your company’s name, or the mill’s?
- Which components are covered, and which are excluded?
Ask for the answers in writing before the order is confirmed. A supplier who can produce a method reference and a sample description on request is a supplier who has done this before. For how testing slots into your wider fabric approval, see our fabric specification library.
One Honest Note
A test report is evidence, not a guarantee.
We can send you reports with named methods, sample descriptions and conditions for every parameter you specify. We cannot promise that a report issued for a sample describes the goods months later, and we do not ask buyers to treat it that way. If your program depends on it, run independent testing on arrival — most importers do, and it is cheaper than a recall.
FAQ
Q: Which laboratory should I use — SGS, Intertek or someone else?
A: The laboratory name matters less than two things: that it is accredited for the specific methods, and that the report names the method, the sample and the conditions. Recognised international laboratories are generally accepted by retailers, but accreditation scope is worth checking for the specific test.
Q: How old can a test report be?
A: There is no fixed rule, but the report should describe the fabric you are actually buying. If the fibre, the weight, the finish or the dye method changed, the report no longer applies. Reports from a previous production run are useful for comparison, not for compliance.
Q: Should I test every lot or every colour?
A: It depends on your risk. On a repeating program, testing one lot per season and comparing lots against the retained standard is common practice. On a first order, or after any change of mill, yarn or finish, test the lot. Where colour is critical, test per colour.
Q: What is a good shrinkage number for loungewear?
A: There is no universal figure, because it depends on the fabric, the knit structure and how the garment is cared for. What matters is that you state the wash programme and the acceptable range in your tech pack, then hold every report against that same programme. Comparing a number without the method is where buyers get into arguments they cannot win.
CTA
Send us your spec with the parameters you need tested. We will return reports that name the method, the sample and the conditions for each one — and tell you plainly which of them we cannot support.