Microbiological Testing & Consulting, LLC MARCS-CMS 720374 — March 16, 2026

WARNING LETTER

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• Delivery Method: VIA EMAIL WITH READ RECEIPT
• Reference #: 320-26-53
• Product: Drugs

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• Recipient: Ms. Lauren Szarzynski; Owner ; Microbiological Testing & Consulting, LLC; 5661 W. 120th Street; Alsip, IL 60803; United States; lauren@mtcresearch.com

• Issuing Office: Center for Drug Evaluation and Research (CDER); United States

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Warning Letter 320-26-53

March 16, 2026

Dear Ms. Szarzynski:

The United States Food and Drug Administration (FDA) inspected your contract testing laboratory, Microbiological Testing & Consulting, LLC, FEI 3003875820, at 5661 W. 120th Street, Alsip, from September 8 to 16, 2025.

This warning letter summarizes significant violations of Current Good Manufacturing Practice (CGMP) regulations for finished pharmaceuticals. See Title 21 Code of Federal Regulations (CFR), parts 210 and 211 (21 CFR parts 210 and 211).

Because your methods, facilities, or controls for manufacturing, processing, packing, or holding do not conform to CGMP, the drug products you tested are adulterated within the meaning of section 501(a)(2)(B) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 351(a)(2)(B).

We reviewed your September 30, 2025, response to our Form FDA 483 in detail and acknowledge receipt of your subsequent correspondence.

During our inspection, our investigators observed specific violations including, but not limited to, the following.

1. Your firm failed to establish laboratory controls that include scientifically sound and appropriate specifications, standards, sampling plans, and test procedures designed to assure that components, drug product containers, closures, in-process materials, labeling, and drug products conform to appropriate standards of identity, strength, quality, and purity. Your firm also failed to conduct appropriate laboratory testing, as necessary, for each batch of drug product required to be free of objectionable microorganisms (21 CFR 211.160(b) and 21 CFR 211.165(b)).

Your firm is a contract testing laboratory that conducts testing of various application and nonapplication drug products for your customers. You failed to conduct appropriate testing to ensure that the results your firm provided to customers were accurate and scientifically sound.

Lack of Adequate Documentation

Your firm lacks significant CGMP documentation for your microbiological testing. For example, you routinely failed to document specific attributes of each test such as:

• equipment number
• sample size
• media batch number
• sample dilutions
• incubation temperatures
• name/signature of performing analyst

According to your personnel, your firm also lacked adequate equipment logs to track usage and maintenance.

Your response is inadequate. You commit to performing a comprehensive review of your testing operations and records. Based on the outcome of the review, your firm plans to update the affected data and test forms. You did not provide specific details on the records, equipment, and data that will be evaluated, nor did you commit to conducting a full retrospective review of test results provided to your customers.

Additionally, you indicate that going forward you will meet standards for laboratory studies. Please note that appropriate regulatory requirements for laboratories conducting testing for drug product manufacturers are 21 CFR parts 210 and 211 and Section 501(a)(2)(B) of the FD&C Act.

Laboratory investigations cannot be performed when systems, procedures, and documentation are deficient.

Complete and accurate records are necessary to ensure that test methods are consistently followed and reproducible. Additionally, complete test records are necessary to reliably conduct record reviews and adequately investigate deviations and drug product failures.

Lack of Appropriate Media Qualification

You lack adequate controls to ensure the reliability of your microbiological testing results. For example, the media used to test your customers drug products was inadequately qualified. You lacked screening for inhibitory properties of your incoming lots of (b)(4).

In your response, you commit to reviewing your tests and methods to identify gaps and implement the appropriate remediation.

Your response is inadequate because you did not commit to pausing testing until assessments are complete, nor did you implement any interim corrective actions. Furthermore, your firm did not provide a plan to re-assess results that have been communicated to customers.

In response to this letter, provide:

• A comprehensive independent assessment of your laboratory practices, procedures, methods, test results, equipment, documentation, and analyst competencies. Based on this review, provide a detailed plan to remediate and evaluate the effectiveness of your laboratory system.
• A retrospective risk assessment of gaps found in your growth media qualification and suitability testing practices over the past three years. Describe how these gaps will be remediated to ensure reliable microbial enumeration and appropriate identification of objectionable microorganisms.
• A complete assessment of documentation systems used throughout your laboratory operations to determine where documentation practices are insufficient. Include a detailed corrective action and preventive action (CAPA) plan that comprehensively remediates your firm’s documentation practices to ensure you retain attributable, legible, complete, original, accurate, contemporaneous records throughout your operation.

2. Your firm’s quality control unit failed to exercise its responsibility to ensure drug products manufactured are in compliance with CGMP and meet established specifications for identity, strength, quality, and purity (21 CFR 211.22).

Your firm lacks appropriate systems and procedures for quality oversight of laboratory testing, documentation, and investigations.

As noted in the prior charge, your quality unit did not have adequate oversight of documentation, media qualification, and other critical microbiology laboratory programs. In addition, you lacked adequate systems for investigations and ensuring analyst competencies.

Furthermore, your management stated that in the past two years your firm conducted only one product out-of-specification (OOS) investigation and one water out-of-limit (OOL) for total aerobic microbial count (TAMC) investigation. These two investigations were the only ones available for our investigator to review. However, records collected during an FDA inspection of one of your customers (b)(4), indicated that your firm reported several OOL for TAMC and objectionable microorganism results within the past two years. It appears that your firm did not make all requested OOS/OOL test data available during the inspection.

In your response, you commit to implement a multiphase OOS investigation methodology. Your response is inadequate. You did not commit to assessing previous OOS results to ensure the investigations were adequate.

Be reminded that it is your responsibility to ensure all data and information provided are accurate, complete, and readily available for inspection. As a contract laboratory, you must comply with the CGMP regulations that apply to operations you perform, including, but not limited to, those that address the operations of your quality control unit, laboratory, investigation system, and documentation system.

Training Program

Your training program is inadequate. CGMP training is not regularly performed at your firm as required by your established procedure. During the inspection, you could not provide records of CGMP training.

In your response, you state a consultant will assess your training procedure for general CGMP requirements and a suitable CGMP training program shall be developed.

Your response is inadequate. You do not provide any immediate steps to address the training program to ensure all employees are adequately trained to complete CGMP activities. Nor do you commit to stop testing until employees can receive appropriate CGMP training.

In response to this letter, provide:

• A retrospective, independent review of all invalidated OOL/OOS (including raw material, in-process, and release/stability testing) results for the last three years from the initial date of inspection and a report summarizing the findings of the analysis, including the following for each OOL/OOS:
  o Provide a list of all OOS and OOL results that were not investigated and your corresponding corrective actions including a reassessment of all instances to determine any additional action needed related to nonconforming results.
  o For each OOL/OOS include your CAPA and how you will ensure all OOS and OOL results will be investigated and communicated in a timely manner to your customer(s) on the certificate of analysis for appropriate follow up.
  o Determine whether the scientific justification and evidence relating to the invalidated OOL/OOS result conclusively or inconclusively demonstrates causative laboratory error.
  o For investigations that conclusively establish laboratory root cause, provide rationale and ensure that all other laboratory methods vulnerable to the same or similar root cause are identified for remediation.
  o An explanation for the discrepancy in the number of OOL and objectionable microorganism investigations that you provided to our investigator compared with the number that you provided to your customer, (b)(4).
• A comprehensive review and remediation plan for your OOL/OOS result investigation systems. The CAPA should include but not be limited to addressing the following:
  o Quality unit oversight of laboratory investigations
  o Identification of adverse laboratory control trends
  o Resolution of causes of laboratory variation
  o Adequate scoping of each investigation and its CAPA
  o Assurance that data, findings, and supporting documentation relating to any OOS/OOL result are promptly conveyed to customers
  o Revised OOL/OOS investigation procedures with these and other remediations
• A description of how top management supports quality assurance and reliable test operations including, but not limited to, timely provision of resources to proactively address emerging quality issues and to assure a continuing state of control.
• Documentation of training for all relevant personnel on revised policies, procedures, and other associated items.

Data Integrity Remediation
Your quality system does not adequately ensure the accuracy and integrity of data to support the safety, effectiveness, and quality of the drugs you test. See FDA’s guidance document Data Integrity and Compliance With Drug CGMP: Questions and Answers for guidance on establishing and following CGMP compliant data integrity practices at https://www.fda.gov/media/119267/download.

We strongly recommend that you retain a qualified consultant to assist in your remediation. In response to this letter, provide:

• A comprehensive investigation into the extent of the inaccuracies in data records and reporting including results of the data review for drugs distributed to the United States. Include a detailed description of the scope and root causes of your data integrity lapses.
• A current risk assessment of the potential effects of the observed failures on the quality of your drugs. Your assessment should include analyses of the risks to patients caused by the release of drugs affected by a lapse of data integrity and analyses of the risks posed by ongoing operations.
• A management strategy for your firm that includes the details of your global corrective action and preventive action plan. The detailed corrective action plan should describe how you intend to ensure the reliability and completeness of all data generated by your firm including microbiological and analytical data, manufacturing records, and all data submitted to FDA.

Responsibilities of Contract Testing Lab
FDA considers contractors as extensions of the manufacturer’s own facility. Your failure to comply with CGMP may affect the quality, safety, and efficacy of the drugs you test for your customers. It is essential that you understand your responsibility to operate in full compliance with CGMP, and that you inform all your customers of any OOS results or significant problems encountered during the testing of these drugs.

CGMP Consultant Recommended

Based upon the nature of the violations we identified at your firm; you should engage a consultant qualified as set forth in 21 CFR 211.34 to assist your firm in meeting CGMP requirements.

Your use of a consultant does not relieve your firm’s obligation to comply with CGMP. Your firm’s executive management remains responsible for resolving all deficiencies and systemic flaws to ensure ongoing CGMP compliance.

Conclusion

The violations cited in this letter are not intended to be an all-inclusive list of violations that exist at your facility. You are responsible for investigating and determining the causes of any violations and for preventing their recurrence or the occurrence of other violations.

Correct any violations promptly. Failure to promptly and adequately address this matter may result in regulatory or legal action without further notice including, without limitation, seizure and injunction. Unresolved violations may also prevent other Federal agencies from awarding contracts.

Failure to address violations may also cause FDA to withhold issuance of export certificates. FDA may withhold approval of new applications or supplements listing your firm as a drug manufacturer until any violations are completely addressed and we confirm your compliance with CGMP. We may re-inspect to verify that you have completed corrective actions to address any violations.

This letter notifies you of our findings and provides you an opportunity to address the above deficiencies. After you receive this letter, respond to this office in writing within 15 working days¹. Specify what you have done to address any violations and to prevent their recurrence. In response to this letter, you may provide additional information for our consideration as we continue to assess your activities and practices. If you cannot complete corrective actions within 15 working days, state your reasons for delay and your schedule for completion.

Send your electronic reply to CDER-OC-OMQ-Communications@fda.hhs.gov. Identify your response with FEI 3003875820 and ATTN: Marva Taylor.

Sincerely,
/S/

Francis Godwin
Director
Office of Manufacturing Quality
Office of Compliance
Center for Drug Evaluation and Research

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1 Under program enhancements for the Generic Drug User Fee Amendments (GDUFA) reauthorization for fiscal years (FYs) 2023-2027, also known as the GDUFA III Commitment Letter, your facility may be eligible for a Post-Warning Letter Meeting to obtain preliminary feedback from FDA on the adequacy and completeness of your corrective action plans.