FDA Warning Letter Highlights Responsibilities of Contract Testing Laboratories

The U.S. Food and Drug Administration (FDA) has issued a Warning Letter to a contract testing laboratory in Hollywood, Florida. The letter, dated 10 February 2025, was published on 18 February 2025.

During an inspection conducted in September 2024, the authority identified significant violations of Current Good Manufacturing Practice (CGMP) regulations for finished pharmaceuticals.

Test Methods

The FDA stated that the firm did not use suitable methods to test its clients’ over-the-counter (OTC) drug products. One example concerns a microbiological testing method that was not verified to be equivalent to or better than the United States Pharmacopeia (USP) method.

The FDA emphasized the following to the laboratory: "Method suitability testing ensures the method can reliably determine the presence of microbial growth in the drug product. Without evaluating the validity of methods, you lack assurance that the data provided to customers was an accurate reflection of pharmaceutical drug product quality and safety."

Deviations in Temperature and Humidity

The laboratory failed to investigate out-of-range deviations in temperature and humidity readings of its equipment. FDA investigators found that a 2–8 °C refrigerator was out of range for more than 24 hours, reaching temperatures of up to 17.4 °C. This refrigerator contained reference microorganisms used in growth promotion tests, yet the deviation was neither identified nor investigated.

Responsibilities of Contract Testing Laboratory

The FDA reiterated the following: "FDA considers contractors as extensions of the manufacturer’s own facility. [...] Failure to comply with CGMP may affect the quality, safety, and efficacy of the drugs [tested for] clients." For a contract testing laboratory, it is essential "to operate in full compliance with CGMP" and to inform the "customers of any out-of-specification (OOS) results or significant problems encountered during the testing".

The FDA has instructed the firm to implement corrective actions, including an independent assessment of laboratory practices, the adoption of validated testing methods, and a thorough review of past test results.

For further information, please refer to the complete Warning Letter to ABR Laboratory LLC, published on the FDA’s website.