NABL accreditation is formal recognition that a laboratory is competent to carry out specific tests or calibrations. It is granted by the National Accreditation Board for Testing and Calibration Laboratories (NABL), a constituent board of the Quality Council of India, after assessing the laboratory against the international standard ISO/IEC 17025. The accreditation does not cover the laboratory as a whole. It covers a defined list of tests, products and methods called the scope of accreditation, at a named location, for a stated period. That is why the most useful question about any “NABL report” is not whether the lab is accredited, but whether this test on this product to this method is in its scope.
NABL in brief
NABL accredits:
- Testing and calibration laboratories against ISO/IEC 17025
- Medical laboratories against ISO 15189
- Proficiency testing providers against ISO/IEC 17043
- Reference material producers against ISO 17034
NABL is a signatory to the mutual recognition arrangements of the International Laboratory Accreditation Cooperation (ILAC) and the Asia Pacific Accreditation Cooperation (APAC). This supports acceptance of NABL accredited reports in other member economies, although the importing country’s own rules still decide what it accepts.
NABL is the laboratory counterpart of NABCB, which accredits certification and inspection bodies. Aaditech, for example, is an NABCB accredited Type A inspection body under ISO/IEC 17020. That is a different accreditation from NABL, and Aaditech is not itself a NABL accredited laboratory.
What ISO/IEC 17025 requires
ISO/IEC 17025:2017 sets out what a laboratory must do to produce valid results. During assessment, NABL assessors check, among other things:
- Impartiality and confidentiality. The laboratory must identify and manage risks to impartiality, and protect client information.
- Competent personnel. Staff who perform tests, review results and sign reports must be qualified, trained and authorised for those activities.
- Equipment and traceability. Instruments must be calibrated, with results traceable to national or international measurement standards.
- Methods. Standard methods must be verified in the laboratory, and non-standard methods validated.
- Measurement uncertainty. The laboratory must evaluate the uncertainty of its measurements.
- Assuring validity of results. Through proficiency testing, inter-laboratory comparisons and internal checks.
- Reporting. Reports must identify the sample, the method, the results and any deviations, and must be reviewed and authorised.
- A management system covering document control, corrective action, internal audits and management review.
Accreditation is maintained through surveillance and reassessment visits, and NABL can suspend or withdraw it.
“NABL certificate” and scope of accreditation
What people call a NABL certificate is the laboratory’s certificate of accreditation. It shows the laboratory name and address, the accreditation standard, the certificate number and the validity dates. The certificate on its own tells you very little. The important document is the scope annexure that goes with it.
A scope is a table. Each row names the discipline and product group, the product tested, the specific test, and the method or clause the test is performed against. For example, rows from the cable scope behind our IS 694 test list read like this:
| Product | Test | Method |
|---|---|---|
| PVC insulated cables | Conductor resistance | Cl. 4.2 of IS 694, Cl. 7.3 of IS 8130, IS 10810 (Part 5) |
| PVC insulated cables | Insulation resistance | Cl. 5.4, 8.4 of IS 694, Table 1 of IS 5831, IS 10810 (Part 43) |
| PVC insulated cables | Halogen acid gas | Cl. 10.6 of IS 694, IS 10810 (Part 59) |
Three things follow from this:
- Accreditation is test by test. A laboratory accredited for conductor resistance on cables is not automatically accredited for smoke density, or for testing batteries.
- The method matters. A test listed against IEC 60332 is not the same entry as one listed against IS 10810. If your buyer asks for a specific standard, check that standard appears in the method column.
- Editions matter. Standards are revised. IS 7098 (Part 1), for example, was revised in 2025. If a tender or regulator asks for the current edition, check that the scope and the report refer to it.
Our own NABL testing pages are built directly from scope data in this form. Each standard page lists every accredited test with the clause it is performed against, so you can see exactly what a report would cover before you send samples.
How to verify a NABL accredited laboratory
- Search the laboratory on the NABL website. NABL publishes a directory of accredited laboratories that can be searched by name, certificate number, location, discipline and test parameter.
- Check the status and dates. Confirm that the accreditation is current, not suspended or withdrawn, and that it was valid on the date your sample was tested.
- Check the location. Accreditation is granted for a specific site. A laboratory group with several sites may be accredited at one and not another.
- Open the scope. Find your product and each test you need, and check the method column against the standard your buyer or regulator specifies.
- Check the discipline. Testing, calibration and medical scopes are separate. A calibration accreditation does not cover product testing.
How to verify a NABL test report
A genuine NABL accredited report should pass all of these checks:
- NABL symbol and certificate number. Reports issued under accreditation carry the NABL symbol (sometimes combined with the ILAC MRA mark) and the laboratory’s accreditation certificate number. Use of the symbol is governed by NABL’s policy document NABL 133.
- ULR number. NABL requires a Unique Laboratory Report (ULR) number on accredited reports, alongside the laboratory’s own report number. NABL updates the prescribed ULR format from time to time, so treat a missing ULR, rather than an unfamiliar format, as the red flag.
- QR code. NABL has introduced QR-code based report verification. Scanning the code should take you to a record on NABL’s system that matches the report.
- Tests within scope. Every test you rely on should appear in the laboratory’s scope for that product and method. Tests outside the scope must be marked as such on the report.
- Sample and product identification. The model, ratings, size or construction on the report must match the product you are supplying. A report on a 2.5 sq mm cable does not cover a 4 sq mm cable unless the standard or the buyer allows it.
- Standard and edition. The report should name the standard and edition you were asked for.
- Dates. The test dates should fall within the accreditation validity. Many buyers and tender documents also set a maximum age for type test reports, so check the bid conditions.
- Authorised signatory. The report should be signed by a person authorised by the laboratory for that field.
If something does not match, ask the laboratory to explain or amend the report before you submit it. A report rejected at tender evaluation or by a regulator usually costs far more than the test itself.
Is a NABL report enough?
Often, but not always. Most tenders, PSUs, utilities and private buyers accept NABL accredited reports. For BIS certification, however, BIS accepts reports only from laboratories it has recognised for the standard, and a NABL accreditation alone does not make a laboratory BIS-recognised. We explain the difference, with examples, in NABL accredited vs BIS-recognised lab.
How Aaditech can help
Aaditech offers NABL accredited testing across more than 3,200 tests to 48 Indian Standards and many IEC, BS, UL and defence standards. For 20 of those Indian Standards, testing is also available at a BIS-recognised laboratory. Before testing, we confirm what the receiving party will accept, plan the tests against the right edition and clauses, and review the report before you use it.
Browse the accredited tests by category: cables and wires, batteries and cells, household appliances, LED lighting, IT and electronics, UPS, conductors and insulating mats and environmental testing.