The USFDA audit process, also referred to as an FDA inspection, is a structured, risk-based, on-site examination conducted to ensure that facilities manufacturing FDA-regulated products comply with applicable federal laws and Current Good Manufacturing Practices (CGMP).

For pharmaceutical companies, biologics manufacturers, medical device firms, and API manufacturers, understanding the FDA inspection process is critical. A well-managed inspection not only ensures regulatory compliance but also builds trust with global regulators and customers.

What Is the USFDA Audit?

The USFDA audit is a systematic evaluation of manufacturing facilities that produce products regulated by the U.S. Food and Drug Administration. The primary objective of the inspection is to verify compliance with CGMP requirements.

FDA inspections are risk-based, meaning facilities with higher risk profiles—such as sterile manufacturing sites, firms with past violations, or those producing critical drugs are inspected more frequently.

Key Stages of the USFDA Audit

The FDA inspection process follows a sequence of events described below.

1. Pre-Inspection / Notification Stage

In most routine inspections, the FDA provides advance notification to the facility. This notification allows the company to make necessary arrangements and ensure the availability of key personnel, documents, and areas for inspection.

However, it is important to note that:

• For-cause inspections may occur without prior notice
• Surprise inspections are legally permitted by the FDA
• Companies must always be in a state of inspection readiness

The companies must adopt continuous CGMP compliance, not just preparing for audits when notified.

2. Opening Meeting and FDA Form 482

The inspection officially begins with an opening meeting between FDA investigators and site management.

During this meeting:

• FDA investigators present their official credentials
• FDA Form 482 (Notice of Inspection) is issued
• The scope and purpose of the inspection are explained

The Form 482 legally authorizes FDA investigators to inspect the facility. From this point onward, the inspection is considered active.

3. Facility Walkthrough and On-Site Inspection

Following the opening meeting, investigators conduct a physical walkthrough of the facility. This is one of the most critical stages of the USFDA audit process.

Typical areas inspected include:

• Manufacturing and production areas
• Quality Control laboratories
• Warehouses and storage areas
• Cleanrooms and controlled environments
• Utility systems such as water, HVAC, and compressed air

Investigators observe:

• Actual practices versus written procedures
• Personnel hygiene and gowning practices
• Equipment condition and cleanliness
• Material flow and segregation

Any mismatch between documented procedures and real-time practices can raise compliance concerns.

4. Document Review and Staff Interviews

After or during the walkthrough, FDA investigators review of documentation and directly interact with personnel.

Common documents reviewed include:

• Standard Operating Procedures (SOPs)
• Batch manufacturing and testing records
• Training records
• Equipment calibration and maintenance records
• Validation and qualification documents
• Deviation, CAPA, and change control records
• Facility layouts

Investigators may interview:

• QA and QC staff
• Production operators
• Supervisors and department heads

Employees are expected to answer questions clearly based on documented procedures and actual practices.

5. Closing Meeting and FDA Form 483

At the conclusion of the inspection, the FDA conducts a closing meeting with site management.

During this meeting:

• Investigators summarize their observations
• Any significant CGMP deficiencies are discussed
• FDA Form 483 (Inspectional Observations) may be issued

A Form 483 lists observed conditions by investigator’s judgment that may constitute violations of FDA regulations. Receiving a Form 483 does not automatically mean regulatory action, but it requires immediate attention and corrective measures.

6. Post-Inspection Response and Reporting

After receiving a Form 483, the inspected firm is must submit a written response, usually within 15 working days.

The response should include:

• Acknowledgment of observations
• Root cause analysis
• Corrective and Preventive Actions (CAPA)
• Implementation timelines and evidence

The FDA reviews the response and determines the final inspection classification, which may include:

• No Action Indicated (NAI)
• Voluntary Action Indicated (VAI)
• Official Action Indicated (OAI)

The quality of the post-inspection response plays a major role in the FDA’s final decision.

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Types of FDA Inspections

The USFDA conducts different types of inspections based on regulatory needs.

1. Surveillance Inspections

Surveillance inspections are routine inspections that FDA conducts to monitor ongoing compliance with CGMP requirements. These inspections help the FDA assess whether a facility continues to operate in a state of control.

2. Pre-Approval Inspections (PAI)

Pre-Approval Inspections are conducted as part of the review of a new drug application (NDA), ANDA, or biologics application.

The FDA verifies:

• Data integrity
• Manufacturing capability
• Consistency between application data and on-site practices

Approval of the product is closely linked to the outcome of this inspection.

3. For-Cause Inspections

For-cause inspections are targeted inspections triggered by specific concerns, such as:

• Product complaints
• Recalls
• Adverse events
• Previous serious violations

These inspections are often more focused and intense than routine inspections.

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