Reviewed and Approved by Shelly Blackwell, Senior Director, Dietary Supplements and Tobacco, EAS Consulting Group, a Certified Group company
1-Minute Summary
- Manufacturers should audit a contract lab’s personnel, test methods, equipment, and quality systems as part of a qualification program to ensure it meets regulatory requirements.
- Test methods must be scientifically valid, properly documented, and consistently followed by trained laboratory personnel.
- A strong quality system, including processes for handling OOS results and deviations, is essential for reliable and compliant testing.
- Choosing a qualified lab upfront helps prevent compliance failures, protects consumers, and safeguards brand reputation.
The Role of Contract Laboratories in Dietary Supplement Testing
Contract laboratories provide critical testing services for dietary supplement manufacturers and own-label distributors, ensuring compliance with 21 CFR 111 (cGMPs). While some companies have in-house labs, many rely on contract labs for specialized analyses requiring advanced expertise or equipment.
However, a contract lab may not meet the necessary regulatory and quality standards. A thorough audit is essential to verify compliance, ensure accurate results, and protect both consumers and brand reputation.
In this article, we provide tips for how to audit a contract lab used to test dietary supplements.
How to Audit a Contract Laboratory
A contract laboratory must demonstrate compliance with the applicable subparts of 21 CFR 111 and possess the expertise, equipment, and processes necessary to produce accurate, reliable, and scientifically valid test results. To determine whether a lab meets these requirements, manufacturers and own-label distributors should establish a contract laboratory qualification program and evaluate the following during an audit:
Personnel Qualifications and Training
Under 21 CFR 111.12(c), laboratory personnel must have appropriate education, training, or experience to perform their job functions competently. A well-qualified laboratory should provide…
- Formal job descriptions outlining specific responsibilities.
- Training records that document on-the-job training.
- Resumes or biographies of key laboratory personnel.
During an audit, review these documents to ensure that staff possess the necessary scientific expertise to perform required tests. Additionally, verify that training is ongoing and documented to maintain high testing standards.
Laboratory Facilities and Equipment
A laboratory’s physical infrastructure and equipment must comply with 21 CFR 111.310, ensuring it is adequate for the testing being performed. In addition…
- Equipment must be of appropriate design, construction, and workmanship in accordance with 21 CFR 111.27.
- An equipment qualification program should be in place to confirm instruments are suitable for their intended use.
- Documentation that supports equipment validation and calibration must be available for review.
- Software and electronic operations used in testing should be assessed for accuracy, security, and compliance with data integrity principles.
Compliance with 21 CFR Part 11 (Electronic Records and Signatures)
If a contract laboratory creates an electronic record to comply with cGMPs, they must also comply with 21 CFR Part 11. Auditors should determine…
- Whether electronic systems are used for generating official test results or recordkeeping.
- If applicable, whether these systems meet Part 11 requirements for security, audit trails, and data integrity.
Regardless of whether Part 11 applies, all laboratory equipment must be properly calibrated and maintained, as required under 21 CFR 111.35(b)(3).
Ensuring Test Methods are Scientifically Valid
Laboratory Procedures and Test Method Validation
A laboratory must have written procedures for test methods, as required by 21 CFR 111.325. These procedures should be well-documented, standardized, and implemented to ensure that testing is conducted consistently and accurately.
During an audit, companies should verify that…
- Laboratory personnel follow test methods exactly as written.
- Documentation of test execution includes details on every step of the process.
- All test methods used are scientifically valid, as required under 21 CFR 111.75(h)(1) and 111.320(b).
What Defines a Scientifically Valid Test Method?
While 21 CFR 111 does not explicitly define “scientifically valid,” the FDA discusses this concept in the preamble to the regulation. According to the FDA, a test method is considered scientifically valid if it demonstrates…
- Accuracy – Produces results that correctly reflect the sample’s true characteristics.
- Precision – Provides consistent and reproducible results across multiple trials.
- Specificity – Can detect the intended analyte without interference from other substances.
- Ruggedness – Maintains performance across different conditions (e.g., different laboratories, analysts, or instruments).
Documentation proving scientific validity may include:
- Method validation studies performed for the specific sample matrix.
- Peer-reviewed scientific literature supporting the method’s accuracy.
- Compendial sources such as USP, AOAC, or other recognized standard-setting organizations.
Auditors should review method validation data during their assessment to confirm that testing methods meet industry and regulatory expectations.
Assessing Quality Systems and Handling of Non-Conforming Results
Out-of-Specification (OOS) Investigations
A laboratory’s handling of Out-of-Specification (OOS) results reflects its commitment to quality and compliance. A robust OOS investigation process should include the following:
- Clear procedures for identifying, documenting, and investigating OOS results.
- Root cause analysis to determine whether the issue stems from testing error, sample contamination, or an actual product failure.
- Corrective and Preventive Actions (CAPA) to address problems and prevent recurrence.
Deviations and Corrective Actions
A strong laboratory quality system must include protocols for handling deviations from standard operating procedures (SOPs). The presence of an effective CAPA system ensures that the laboratory actively works to improve processes and maintain compliance.
Choosing the Right Laboratory Partner
Vetting a lab upfront minimizes risks, prevents costly mistakes, and ensures products meet regulatory requirements.
Need expert guidance on auditing a contract lab? EAS Consulting Group, a Certified Group company, can help. If you require supplement testing, Certified Laboratories offers comprehensive services.