FDA Warning Letter to Abbott Diabetes Care — Key Quality System Failures

Recently the U.S. Food and Drug Administration issued a Warning Letter to Abbott Diabetes Care following a routine inspection of their Alameda, CA facility that raised serious Quality System Regulation (21 CFR Part 820) violations in the manufacture of FreeStyle Libre continuous glucose monitoring (CGM) systems.

The FDA concluded that the devices are adulterated because manufacturing methods and controls do not conform to federal quality requirements.
Core Regulatory Failures Identified:
1. Broken Design Transfer Controls (21 CFR § 820.30(h))
Abbott failed to ensure that device design requirements — especially glucose accuracy performance specs — were properly flowed down to contract manufacturers.
2. Inadequate Finished Device Acceptance Controls (21 CFR § 820.80(d))
Abbott admits it does not performance-test fully assembled, sterilized, and packaged CGM devices for accuracy before distribution — instead relying on upstream component testing.
3. Lack of Statistically Valid Sampling & Acceptance Criteria (21 CFR § 820.250(a))
Statistical plans for sampling and acceptance thresholds are poorly supported by valid statistical rationale.
4. Poorly Validated Manufacturing and Release Controls (21 CFR § 820.30(g))
Abbott did not demonstrate that its manufacturing and release processes preserve device performance validated in pre-market studies.
FDA’s Assessment of Abbott’s Responses:
Abbott submitted two responses (Nov and Dec 2025), but the FDA found both inadequate: procedural fixes lacked evidence of implementation, did not correct root causes, and failed to provide objective data verifying control effectiveness.
Take-Away for Industry Leaders:
This Warning Letter exemplifies how gaps in design transfer, finished-product acceptance testing, statistical process control, and validation rigor can undermine the integrity of a regulated quality system — even for widely used medical devices.