In multicenter trials, what should be provided when investigators collect additional data beyond the core protocol?

• A. Supplemental CRFs should be provided to capture the additional data.
• B. Additional data should not be captured separately.
• C. The same CRFs used in core data should be reused for all data types.
• D. Data collection is delegated to investigators without CRFs.

Answer: (A)

When investigators collect data beyond what the core protocol specifies, add supplemental CRFs to capture that extra information. This creates a formal, standardized way to document additional data across all sites, ensuring consistency in definitions, data entry, and coding, and providing a clear audit trail for monitoring, QC, and regulatory review. Supplemental CRFs help keep core endpoints distinct from ancillary data while still enabling full data analysis and traceability.

Not capturing extra data separately would lead to unstructured notes or ad hoc entries that are hard to verify or analyze. Reusing the same CRFs for all data types can force mismatches between additional data fields and the core forms, undermining data quality and complicating analyses. Delegating data collection without CRFs eliminates a formal mechanism for documentation and auditing, which is a GCP requirement for reliable, compliant trial data.