298 FDA drug CGMP warning letters from 2023-11-06 to 2026-10-27: 102 of them (34%) cite problems in this area: OOS results not investigated, results invalidated without cause, testing into compliance, methods not validated. Below, each problem FDA cites, how often, where the records that show it live, and how a plant can find it in its own records.
What FDA cites
| Problem | Records in | Letters |
|---|---|---|
| Methods not validated or suitability not shown How to find it: List the methods used for release (LIMS) and check each has a validation or verification report (DMS); the plant confirms. FDA wrote, for example: “Failing micro results invalidated by retesting without justification.” | LIMS / CDS, Documents (DMS) | 46 · 15.4% |
| OOS results with no investigation Cross-system How to find it: List every out-of-specification result in the LIMS and look for its investigation in the QMS (sample, batch, test, date); flag those with none. FDA wrote, for example: “Microbial OOS component results invalidated by averaging.” | LIMS / CDS, QMS | 38 · 12.8% |
| Lab records incomplete (raw data, calculations, missed samples) How to find it: Flag results without raw data attached, without a reviewer, or reviewed by the analyst who did them; and scheduled samples with no result. FDA wrote, for example: “Micro lab records incomplete/unreliable, indicating falsified test data.” | LIMS / CDS | 31 · 10.4% |
| OOS results invalidated without an assignable cause Cross-system How to find it: For OOS results marked invalid: the root cause recorded, and how often 'analyst error' or 'lab error' is used per analyst and method; flag invalidations without evidence and repeated patterns. FDA wrote, for example: “Microbial OOS component results invalidated by averaging.” | QMS, LIMS / CDS | 17 · 5.7% |
| Instruments used past calibration or qualification Cross-system How to find it: For each test: the instrument used and its calibration / qualification status that day; flag tests on overdue instruments. FDA wrote, for example: “Test records lacked key details; media not qualified; equipment logs inadequate.” | LIMS / CDS, eLogbooks / CMMS | 12 · 4.0% |
| Testing into compliance (retests until it passes) How to find it: Flag samples tested more than once where only a passing result was reported, and retests without an approved investigation. FDA wrote, for example: “Microbial OOS component results invalidated by averaging.” | LIMS / CDS | 10 · 3.4% |
Read the warning letters, one by one · All the figures
Other areas
How these figures are made: Siddhi LLC reads FDA's public drug CGMP warning letters (on fda.gov, 2023-11-06 to 2026-10-27: 298 letters, 1315 findings) and groups each finding by the problem it describes, from the CFR section FDA cites and FDA's wording. A letter counts once in an area, and can count in several areas. These are our grouping of FDA's letters, not FDA's own statistics. The systems are where a plant keeps the records that show each problem: FDA cites the regulation, not a system. Updated with each new release of the Atto Audit Library.
Find these problems in your own records before an inspector does
The Atto Auditor compares the exports of your MES, QMS, LIMS, training, documents, logbooks and ERP, whichever vendors made them, and gives your plant's Audit fit summary: each problem FDA cites, with the records that show it.