How to lock a clinical trial database

Database lock is the point where you freeze the clinical data so no one can change it, and hand it to the statistician for the final analysis. You get there by closing every open item on a checklist, collecting the sign-offs and removing edit rights. A clean lock depends on the weeks before it, since every open query becomes a delay.

Soft lock and hard lock

A soft lock, sometimes called a freeze, stops data entry on a form, a visit or a patient while the team reviews. Changes stay possible through a controlled process. The hard lock is final: nobody can edit the data, and an unlock needs a documented reason and approval.

The lock checklist in 7 steps

1. All data entered. Every expected form for every patient is complete, or marked as not done with a reason.
2. All queries closed. No open query remains, and the team has reviewed every answered one.
3. Source data verification done. Monitors have verified the fields your monitoring plan marks as critical.
4. Coding complete and reviewed. Every adverse event, medical history term and medication carries a code.
5. Reconciliations done. Serious adverse events match the safety database, and external data such as lab results match the EDC.
6. Sign-offs collected. Investigators sign their patients' data, and the data manager, statistician and sponsor sign the lock form.
7. Lock and export. Remove edit rights, lock the database, and export the final datasets with the audit trail.

Mistakes that delay the lock

• Starting the checklist after the last visit. Run it every month in the final quarter of the study.
• Late investigator signatures. Book the signing sessions with sites before the last patient's last visit.
• No unlock procedure. A late finding after lock, with no written process, turns into an inspection issue.

Lock in Datacapt

Datacapt covers the steps before lock inside the study: review, source data verification, lock and signature of the clinical data. Monitors see which flagged fields still need verification, and data managers mark pages reviewed as they go. Exports come in CSV, XLSX, PDF and SAS formats. You lock a form, a visit or a whole eCRF, and Datacapt refuses the lock while a query on that form stays open. A user with lock rights can remove a lock, so record the reason and the approval in your unlock procedure.

Keep reading

• Regulatory compliance of EDC systems
• Datacapt EDC