Published on 21/12/2025

How to Conduct Source Data Verification (SDV) in Clinical Trials

Source Data Verification (SDV) is a key component of clinical trial monitoring. It ensures that data entered into case report forms (CRFs) or electronic data capture (EDC) systems accurately reflect the source documents maintained at the clinical site. This tutorial provides a step-by-step guide for Clinical Research Associates (CRAs) and site staff to perform SDV efficiently, in alignment with regulatory and sponsor expectations.

Table of Contents

What Is Source Data Verification (SDV)?

SDV is the process of comparing data recorded in the trial database to the original source data — such as patient charts, lab reports, or signed informed consent forms. As per USFDA and EMA guidance, SDV is a critical activity that supports the integrity, reliability, and credibility of clinical trial data.

Types of Source Documents in Clinical Trials

Hospital medical records (paper or electronic)
Clinic progress notes
Signed informed consent forms (ICFs)
Laboratory test reports
Imaging reports (e.g., CT, MRI)
Subject diaries and questionnaires
Investigational product (IP) accountability records

When Is SDV Performed?

SDV typically occurs during Routine Monitoring Visits (RMVs), Interim Monitoring Visits, or Close-out Visits. It is guided by the monitoring plan, protocol-specific requirements, and risk-based monitoring strategies. Sites handling high-risk trials or critical data points

(e.g., primary endpoints or safety data) undergo more frequent SDV.

Step-by-Step SDV Process for CRAs

Step 1: Review Pre-Visit SDV List

Download the SDV checklist or plan from the CTMS
Focus on subject visits flagged by the sponsor (e.g., first patients, SAE cases)
Review pending data entry in EDC and missing forms

Step 2: Verify Informed Consent

Ensure subject signed the latest IRB-approved ICF version
Check date/time against study procedures (must be signed before any procedure)
Confirm witness or translator signatures if applicable

Step 3: Compare EDC Entries with Source

Verify subject demographics, inclusion/exclusion criteria
Cross-check vital signs, labs, and adverse events
Ensure IP administration dates match dispensing logs
Confirm visit dates align with subject calendars and protocol schedule

Step 4: Document Discrepancies

Flag any discrepancies in SDV notes or CRA worksheets
Query unresolved differences in EDC and note justification
Discuss with site staff and request updates or clarifications

Step 5: Sign Off SDV Completion

Once the verification is complete for a visit, the CRA should:

Mark SDV status as complete in EDC (if system allows)
Update CTMS visit report with SDV summary
Note any findings in the Monitoring Visit Report (MVR)

Difference Between SDV and SDR (Source Data Review)

While SDV focuses on the exact data match between CRFs/EDC and source, Source Data Review (SDR) involves a broader assessment of documentation completeness, protocol adherence, and overall data quality. For example, checking whether a lab result was reviewed by the PI is part of SDR, not SDV.

Best Practices for Efficient SDV

Organize source files by subject and visit
Highlight sections to be verified using color-coded tabs
Use digital source documents when permitted, following 21 CFR Part 11
Maintain SDV logs to track pending or partial verifications
Train site coordinators in SDV preparation using SOP templates

How Sponsors Use SDV Metrics

Sponsors analyze SDV completion rates, error trends, and CRA visit timelines to monitor trial quality. A sudden rise in discrepancies may prompt closer scrutiny or targeted re-training. Sponsors may also compare SDV rates with quality indicators from Stability Studies or risk-based monitoring platforms.

Regulatory Expectations for SDV

Regulators expect documented evidence of SDV activity. During inspections, agencies like the CDSCO or Health Canada may request:

Signed CRA SDV checklists
Monitoring Visit Reports with SDV coverage summaries
Follow-up documentation of discrepancies

Conclusion

Source Data Verification is a cornerstone of clinical trial quality. By following structured steps and best practices, CRAs and site staff can ensure data consistency, reduce regulatory risk, and build confidence in the trial results. Effective SDV not only improves data reliability but also demonstrates a strong compliance culture, essential for successful trial completion and future audits.