FDA Technical Conformance Guide

The FDA Study Data Technical Conformance Guide (TCG) defines requirements for electronic study data submissions. This page covers XPT-specific requirements.

Submission Types

XPT files are required for these FDA submission types:

File Size Requirements

graph LR
    subgraph "File Size Limits"
        A[Single XPT] --> B{">5 GB?"}
        B -->|Yes| C[Split into parts]
        B -->|No| D[Single file OK]
        C --> E[ae_001.xpt<br/>ae_002.xpt<br/>...]
    end

Automatic File Splitting

xportrs automatically handles file splitting:

#![allow(unused)]
fn main() {
use xportrs::Xpt;

// Automatically splits if dataset would exceed 5GB
Xpt::writer(large_dataset)
.max_file_size_gb(5.0)  // Optional, 5.0 is default
.finalize() ?
.write_path("ae.xpt") ?;  // May create ae_001.xpt, ae_002.xpt, ...
}

Character Encoding

[!IMPORTANT] FDA requires **ASCII-only ** characters in variable names and labels. Extended characters may cause validation failures.

ASCII Validation

#![allow(unused)]
fn main() {
use xportrs::{Agency, Xpt};

let validated = Xpt::writer(dataset)
.agency(Agency::FDA)  // Enforces ASCII validation
.finalize() ?;

// Non-ASCII characters will generate errors
for issue in validated.issues() {
if format ! ("{}", issue).contains("ASCII") {
eprintln ! ("ASCII violation: {}", issue);
}
}
}

Variable Requirements

Naming Conventions

Label Requirements

Numeric Precision

XPT files use IBM floating-point format with specific precision limits:

[!NOTE] For maximum precision, consider using the DATE9. or DATETIME20. formats for date/time values rather than storing as plain numerics.

Date Handling

FDA expects dates in specific formats:

ISO 8601 Character Dates

#![allow(unused)]
fn main() {
// Preferred: Store as ISO 8601 character string
Column::new("AESTDTC", ColumnData::String(vec![Some("2024-01-15".into())]))
.with_label("Start Date/Time of Adverse Event")
.with_format(Format::character(19))
}

SAS Numeric Dates

#![allow(unused)]
fn main() {
// Alternative: Store as SAS date number
// Days since January 1, 1960
let sas_date = 23_391.0;  // 2024-01-15

Column::new("AESTDT", ColumnData::F64(vec![Some(sas_date)]))
.with_label("Start Date")
.with_format_str("DATE9.") ?
}

Study Data Reviewer’s Guide

FDA recommends including a Reviewer’s Guide with submissions. The guide should reference:

• Dataset locations and naming conventions
• Variable naming patterns
• Any deviations from CDISC standards
• Data transformation documentation

eCTD Placement

XPT files are placed in specific eCTD module locations:

m5/
├── datasets/
│   ├── tabulations/
│   │   ├── sdtm/
│   │   │   ├── ae.xpt
│   │   │   ├── dm.xpt
│   │   │   └── define.xml
│   │   └── send/  (nonclinical)
│   └── analysis/
│       └── adam/
│           ├── adsl.xpt
│           ├── adae.xpt
│           └── define.xml

Validation Checklist

Before submission, verify:

• All XPT files ≤5GB (or properly split)
• Variable names ≤8 characters, uppercase
• Variable labels ≤40 characters, ASCII only
• Dataset names ≤8 characters
• Character variable lengths ≤200 bytes
• define.xml present and valid
• Pinnacle 21 validation passed (or issues documented)

Resources

• FDA Study Data Technical Conformance Guide
• FDA Study Data Standards Resources
• FDA Data Standards Catalog