Of all the information on a calibration certificate, as-found and as-left data may be the most valuable for protecting your quality system. Yet some labs treat it as an optional extra. At Field Calibrations, Inc., it's a standard deliverable on every certificate — because it's what protects you when something goes wrong.
What the terms mean
As-found data is the set of measurements taken when the instrument arrives, before any adjustment — it captures the instrument's condition as it was actually used in your process. As-left data is taken after any adjustment or repair, documenting the condition in which the instrument is returned to you. Together they tell the full story of the calibration event.
Why as-found data is the one that matters most
If an instrument comes back in tolerance, great. But if it's found out of tolerance, the critical question is: what product did I make with this instrument since its last calibration? As-found data is the evidence that lets you answer this. Without it, you can't perform a proper impact or reverse-traceability assessment — and you may have to quarantine or recall far more product than necessary.
What ISO 9001 and IATF 16949 require
ISO 9001:2015 clause 7.1.5.2 and IATF 16949 require that, when monitoring or measuring equipment is found unfit for purpose, you assess the validity of previous measurement results and take appropriate action. As-found data is exactly the record you need to satisfy this requirement during an audit. Auditors routinely ask to see it.
What AS9100 expects
Aerospace quality systems built on AS9100 carry the same equipment-monitoring requirements as ISO 9001 plus additional rigor around configuration and traceability. As-found / as-left records support nonconformance investigations and corrective action — and a source inspector reviewing your calibration records expects to see them.
What the FDA expects
For medical-device manufacturers under 21 CFR Part 820 and labs under ISO 13485, calibration records are part of the device master record and quality system. An FDA investigator examining a deviation will look for as-found data to evaluate whether nonconforming product reached the market. Having it readily available is the difference between a contained issue and a major finding.
The FCI standard
Every FCI certificate documents as-found and as-left readings at each test point, with measured values, tolerances, and expanded uncertainty at a 95% confidence level (k=2). This isn't an upgrade — it's how we do calibration. If you're tired of chasing labs for the data your auditors demand, request a quote from FCI and we'll respond within one business day.