How do I read a third-party lab test report for garments?

Main answer

A lab report is only useful if it covers the same fabric and garment you will receive, uses a named method and edition, states the conditions, and says plainly what was measured. Read the sample description, test list and result wording first, and treat a "pass" stamp as meaningless until you know what limit it was measured against.

Who tested it

Check the laboratory’s name, address and whether it is independent of the supplier. ISO/IEC 17025 sets general requirements for the competence of testing and calibration laboratories, and an accreditation covers a defined scope of tests and not the whole laboratory. Ask which tests in the report fall within the lab’s accredited scope, and whether the accreditation body is named.

What was tested

The report should describe the sample: fabric composition, colour, weight, construction and, if relevant, finishing. Compare it with your order. A report on a different colour or an earlier development fabric says little about bulk production. Look for a report date, sample receipt date and a unique report number, so that the document can be traced.

Method, edition and conditions

Each result should show the test method with its edition, for example an ISO or AATCC method. Conditions matter, such as washing programme or conditioning atmosphere. ISO 139 defines standard atmospheres for conditioning and testing textiles, and results depend on them. A result without its method cannot be compared with another report or a requirement.

Result wording

Look for whether the lab reports only measured values or also states a pass or fail. A pass needs a stated requirement, such as your specification or a retailer’s. Note remarks about specimens, deviations and tests not performed. Request a re-test or additional tests where the report does not cover your claim. See also underwear quality and compliance.