What Is a Form 483?
At the close of an FDA inspection, if the investigator identifies conditions that may violate the Food, Drug, and Cosmetic Act, they issue a Form 483 (Inspectional Observations). This is not a final agency action — it is an opportunity for you to respond before FDA decides whether to escalate.
The 15-Business-Day Window
While FDA does not mandate a response timeline, the strong industry standard is to respond within 15 business days. A prompt, substantive response signals good faith and demonstrates your quality culture to FDA. Delayed or inadequate responses significantly increase the risk of a Warning Letter.
Structure of an Effective 483 Response
1. Acknowledge Each Observation
Start by acknowledging the observation without being defensive. Do not argue whether the observation is valid — even if you disagree, focus on corrective actions.
2. Root Cause Analysis
For each observation, document a thorough root cause analysis (RCA). FDA expects you to identify the systemic root cause, not just the surface-level issue. Common RCA tools include:
- 5 Whys
- Fishbone (Ishikawa) diagram
- Fault Tree Analysis
3. Immediate Corrective Actions
Describe what you have already done since the inspection to correct the specific condition observed.
4. Long-Term Preventive Actions (CAPA)
Explain the systemic changes you will implement to prevent recurrence. Include:
- Specific actions with owners assigned
- Realistic target completion dates
- Metrics to verify effectiveness
5. Supporting Documentation
Attach evidence where possible: updated SOPs, training records, revised batch records, corrected labels. Evidence strengthens credibility.
Common Mistakes That Lead to Warning Letters
- Vague commitments ("We will retrain staff") without specifics
- Unrealistic timelines — promising too much too fast looks implausible
- Failure to address root cause — treating symptoms, not causes
- No effectiveness check — CAPA without a verification plan is incomplete
- Ignoring repeat observations — FDA tracks recurrence across inspection cycles
When Observations Are Incorrect
If you believe an observation is factually inaccurate, you may respectfully clarify the facts in your response. Provide data and documentation — but still present a corrective action plan.
After Your Response
FDA will review your response and determine whether to:
- Close the inspection with no further action
- Issue a Warning Letter if the response is inadequate
- Schedule a follow-up inspection
How United Regulatory Can Help
We draft 483 responses, lead root cause analysis, develop CAPA plans, and prepare your team for follow-up FDA contact. Reach out within the first 48 hours of receiving a 483 — time matters.