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483 CFR References

Access CFR references cited in FDA 483 observations, including cross-reference mapping to CTWise regulatory rules and an analytics summary endpoint combining all 483 datasets.

Tier Access

Required Tier: Starter+ (Starter, Pro, Enterprise)

Rate limits apply per tier — see Rate Limits for details.

GET /v1/483/cfr-references/{cfr}​

Retrieve CFR reference detail with cross-reference matches to CTWise regulatory rules.

Request​

GET https://api.ctwise.ai/v1/483/cfr-references?cfr=21%20CFR%20211.113
X-Api-Key: YOUR_API_KEY

Path Parameters​

ParameterTypeRequiredDescription
cfrstringYesCFR reference number (URL-encoded in path, or use ?cfr= query parameter)
tip

CFR references contain spaces (e.g., 21 CFR 211.113). You can either URL-encode the path parameter or use the query parameter ?cfr=21 CFR 211.113 as a convenient alternative.

Response​

{
  "act_cfr_number": "21 CFR 211.113",
  "short_description": "Control of microbiological contamination",
  "occurrence_count": 542,
  "associated_product_types": ["Drugs"],
  "cross_references": [
    {
      "rule_id": "FDA-GMP-MICRO-001",
      "source": "fda",
      "title": "Microbiological Contamination Prevention",
      "similarity_score": 0.85
    }
  ],
  "match_confidence": 0.85,
  "matched_at": "2026-02-15T12:00:00Z",
  "query_metadata": {
    "execution_time_ms": 95
  }
}

Response Fields​

FieldTypeDescription
act_cfr_numberstringCFR reference number
short_descriptionstringBrief description of the regulation
occurrence_countintegerTimes this CFR has been cited in 483s
associated_product_typesstring[]Product types commonly citing this CFR
cross_referencesarrayMatched CTWise regulatory rules
cross_references[].rule_idstringCTWise rule identifier
cross_references[].sourcestringRule source (fda, ich, ema, etc.)
cross_references[].titlestringRule title
cross_references[].similarity_scorenumberSemantic similarity (0-1)
match_confidencenumberOverall cross-reference confidence
matched_atstringWhen cross-referencing was performed

GET /v1/483/cfr-references​

List CFR references with filtering and pagination, sorted by citation frequency.

Request​

GET https://api.ctwise.ai/v1/483/cfr-references?min_occurrence_count=100&limit=10&sort_order=desc
X-Api-Key: YOUR_API_KEY

Query Parameters​

ParameterTypeRequiredDescription
limitintegerNoResults per page (default: 20, max: 100)
offsetintegerNoPagination offset (default: 0)
min_occurrence_countintegerNoFilter by minimum citation count
sort_orderstringNoSort by occurrence_count: asc or desc (default: desc)

Response​

{
  "results": [
    {
      "act_cfr_number": "21 CFR 211.22",
      "short_description": "Responsibilities of quality control unit",
      "occurrence_count": 1245
    },
    {
      "act_cfr_number": "21 CFR 211.113",
      "short_description": "Control of microbiological contamination",
      "occurrence_count": 542
    }
  ],
  "total": 1410,
  "offset": 0,
  "limit": 10,
  "filters_applied": {
    "min_occurrence_count": "100"
  },
  "query_metadata": {
    "execution_time_ms": 78
  }
}

GET /v1/483/analytics/summary​

Cross-dataset analytics summary combining citations, facilities, CFR references, and risk scores.

Request​

GET https://api.ctwise.ai/v1/483/analytics/summary
X-Api-Key: YOUR_API_KEY

Response​

{
  "total_citations": 25522,
  "total_facilities": 8145,
  "total_cfr_references": 1410,
  "risk_distribution": {
    "low": 4200,
    "medium": 2800,
    "high": 900,
    "critical": 245
  },
  "top_cited_cfr": [
    {
      "act_cfr_number": "21 CFR 211.22",
      "short_description": "Responsibilities of quality control unit",
      "occurrence_count": 1245
    }
  ],
  "fiscal_year_breakdown": {
    "2020": 3200,
    "2021": 2800,
    "2022": 4100,
    "2023": 5200,
    "2024": 5800
  },
  "data_freshness": {
    "citations": "25522 records",
    "facilities": "8145 records",
    "risk_scores": "8145 records",
    "cfr_references": "1410 records"
  },
  "query_metadata": {
    "execution_time_ms": 310
  }
}

Examples​

Get Most-Cited CFR References​

curl -X GET "https://api.ctwise.ai/v1/483/cfr-references?min_occurrence_count=100&limit=10" \
  -H "X-Api-Key: YOUR_API_KEY"

Python Example​

import requests

API_KEY = "your_api_key"
BASE_URL = "https://api.ctwise.ai/v1"

# Get CFR detail with cross-references
response = requests.get(
    f"{BASE_URL}/483/cfr-references",
    headers={"X-Api-Key": API_KEY},
    params={"cfr": "21 CFR 211.113"}
)
ref = response.json()

print(f"{ref['act_cfr_number']}: {ref['short_description']}")
print(f"Cited {ref['occurrence_count']} times in FDA 483s")
print(f"\nCross-referenced CTWise Rules:")
for xref in ref['cross_references']:
    print(f"  {xref['rule_id']} ({xref['source']}): {xref['title']}")
    print(f"    Similarity: {xref['similarity_score']:.0%}")

JavaScript Example​

const API_KEY = 'your_api_key';
const BASE_URL = 'https://api.ctwise.ai/v1';

// Get analytics summary
const response = await fetch(`${BASE_URL}/483/analytics/summary`, {
  headers: { 'X-Api-Key': API_KEY }
});
const summary = await response.json();

console.log(`Total Citations: ${summary.total_citations}`);
console.log(`Total Facilities: ${summary.total_facilities}`);
console.log(`\nRisk Distribution:`);
Object.entries(summary.risk_distribution).forEach(([level, count]) => {
  console.log(`  ${level}: ${count}`);
});

Error Responses​

CFR Not Found​

{
  "error": "CFR reference not found: 21 CFR 999.999",
  "status_code": 404
}

Status: 404 Not Found

Performance​

MetricTarget
CFR detail< 1 second
CFR list< 2 seconds
Analytics summary< 3 seconds
Timeout30 seconds

KG Intelligence (Cross-Domain)​