Unit
- Definition: Source data verification (SDV) is the process of comparing data entered in case report forms (CRFs) against original source records to confirm accuracy, completeness, and consistency. This ensures that clinical trial data reflects what actually occurred during the study.
- Purpose: SDV protects patient safety by identifying errors that could lead to incorrect conclusions about a treatment’s safety or efficacy. It also supports regulatory compliance by providing reliable evidence for drug approvals.
- Scope: SDV applies to all data points that support primary and secondary endpoints, as well as safety data. Common source documents include medical records, laboratory reports, imaging files, and patient diaries.
- Key stakeholders: Clinical research associates (CRAs) perform SDV during monitoring visits. Data managers review SDV results and track discrepancies. Investigators and site staff provide access to source records and resolve queries.
- Timing: SDV occurs throughout the trial lifecycle, from first patient visit to database lock. Early verification catches errors before they propagate to later visits or analyses.
- Regulatory basis: ICH Good Clinical Practice (GCP) E6(R2) requires that reported data be accurate, complete, and verifiable from source documents. SDV is a core activity to meet this requirement.
- Benefits: Reliable data leads to credible study results, faster regulatory reviews, and fewer post-marketing issues. It also protects the reputation of sponsors and clinical research organizations.
- Common misconceptions: SDV does not involve rewriting source records or making medical judgments. It is a verification activity, not a therapy or diagnosis.
- Process steps: The CRA reviews each critical data point in the CRF against the corresponding source record. Any discrepancies are documented in a query log and communicated to the site. The site resolves the query, and the CRA confirms the correction before closing the data point.
- Documentation: Every SDV activity must be recorded in monitoring visit reports, including the date, data points checked, findings, and follow up actions. This creates a clear audit trail that regulators and sponsors use to confirm systematic verification throughout the trial.
- Risk based monitoring: Many sponsors now employ risk based approaches that focus SDV on critical data and processes rather than performing 100 percent verification. This strategy allocates resources efficiently while still ensuring data integrity and patient safety.
- Challenges: Common obstacles during SDV include incomplete or illegible source records, time constraints during monitoring visits, and limited access to source documents due to site policies. Clear communication between CRAs and site staff is essential to overcome these difficulties.
Terminology
- Case Report Form (CRF)
- A standardized form used to collect data from each trial participant.
- Source Documents
- Original records where data are first recorded, such as medical charts or lab reports.
- Monitoring Visit
- A periodic review of trial conduct and data by a CRA at the study site.
Quick Revision
- Source data verification compares CRF data to original source records to confirm accuracy.
- SDV protects patient safety and supports regulatory compliance in clinical trials.
- Key stakeholders include CRAs, data managers, and site staff.
- ICH GCP mandates that trial data be verifiable from source documents.