FDA Warning Letter: When Test Procedures Allow Retesting Until an Acceptable Result is Obtained

On 20 October 2026, the U.S. Food and Drug Administration (FDA) posted a Warning Letter dated 28 September 2026 to a manufacturer of OTC drug products in Utah, following an inspection of its facility from 27 April to 1 May 2026.

OOS Investigations

The FDA first describes that the firm routinely failed to investigate out-of-specification (OOS) chemical and microbiological results.

According to the FDA, the firm "retested failing samples or prepared and tested new samples without justification until [the] analysts obtained passing results." The company then "used these results to release drug product to the market without appropriate investigations into the original failing results."

These were not isolated deviations from requirements. On the contrary, the laboratory SOPs themselves permitted repeated retesting. One SOP described repreparing OOS samples and retesting several times without requiring an investigation. Quality control management was notified only after an OOS result, not before retesting began.

The FDA also points to analyst discretion regarding unknown peaks: one procedure left it to the analyst to decide whether to consult QC management about an unidentified chromatographic peak.

The microbiological testing SOP allowed retesting after an initial failure. If the retest also failed, analysts moved to a second microbiological testing system. Failing batch release results from the first system were invalidated, and passing results from the second system were used for release.

The firm could not provide data supporting this tiered approach or showing that one method was superior to the other.

Further Deficiencies

Besides the OOS issue, the FDA describes several further deficiencies:

• Complaint investigations: Complaint investigations relied largely on email correspondence. They lacked proper root cause determination and CAPA. The FDA noted that inadequate investigations were a repeat observation at the firm.
• Component identity and supplier COAs: Identity testing of incoming components was inadequate, representative sampling was not performed for each lot, and results from previously tested lots were sometimes reused for new shipments. Supplier certificates of analysis were accepted without confirmatory testing or evidence of their reliability.
• Quality unit oversight: The FDA found that the quality unit did not exercise its authority effectively.

Requested Actions

The firm must submit a written response within 15 business days of receipt, including:

• An independent assessment of the investigation system and a remediation plan
• A retrospective review of invalidated OOS results for products on the U.S. market and within expiry
• A review of complaints from the past three years, including complaint sample retrieval efforts
• A list of laboratory specifications and test methods, and a retain sample testing plan with results
• An independent review of the material system, including supplier qualification and COA validation
• An assessment of the CAPA program and a remediation plan for the quality unit's authority

The FDA also recommends that the firm engage a qualified consultant to conduct a comprehensive six-system audit.

For further information, please see the complete Warning Letter to SnugZ USA, Inc. on the FDA's website.