FDA Form 483

A Form 483 is issued at the close of an FDA inspection and lists what the investigator observed — conditions that in their judgement may indicate a violation of the FD&C Act or its regulations. It is explicitly a list of observations, not a final agency determination. The distinction is real but narrow in practice: 483 observations are the raw material from which warning letters are built, and the response is what determines which way it goes.

The response window matters enormously. Responding in writing within fifteen business days means the response is considered before FDA decides whether to escalate. A strong response addresses each observation with corrections already taken, corrective actions with owners and dates, an assessment of whether the same problem exists elsewhere in the site, and — where the firm disagrees — a clear factual explanation rather than a bare denial.

The classic failure is treating a 483 as a documentation exercise: promising procedural updates for findings that reveal systemic weakness, addressing only the specific example cited rather than the underlying condition, or committing to dates the site then misses. FDA publishes 483s, and inspection outcomes are classified NAI, VAI, or OAI — with OAI signalling that regulatory action is warranted.

• —Issued at inspection close; observations, not a final determination.
• —Respond in writing within 15 business days to have the response considered before escalation.
• —Address each observation: correction taken, corrective action with owner and date, and scope elsewhere.
• —Assess whether the same condition exists beyond the specific example cited.
• —Disagreement is legitimate — but must be a factual explanation, not a bare denial.
• —Outcomes are classified NAI / VAI / OAI; OAI indicates regulatory action is warranted.

FD&C Act §704(b) (report of observations at the conclusion of an inspection); FDA Investigations Operations Manual; FDA Field Management Directive 145 on 483 practice; publicly released under the Freedom of Information Act.