We have been asked many times during audits about the use of Excel spreadsheets. We have seen numerous examples of uncontrolled excel spreadsheets being used for QC testing.
This example of a warning letter from an August 2011 inspection of an OTC firm, Compañía Internacional de Comercio, S.A. de C.V., in Mexico that highlights the importance of qualifying your Excel spreadsheet.
Excel spreadsheets, when used for calculations, must be qualified. It is difficult to validate the spreadsheets, but companies must manage the spreadsheets in the same manner that they would a software program and controlled documentation.
Here are some tips to consider when working with Excel spreadsheets that calculate formulas and are used to determine the status of the material/product against the specification.
- Put the spreadsheet on the network server in a limited access folder with read-only ability.
- Test the spreadsheet prior to protocol execution (pre-qualification).
- Ensure the precision of final calculations meet the requirements for SOP on rounding and significant figures.
- Ensure that the precision of the final calculations meet the specification requirements
- Document training for spreadsheet users.
- Maintain limited access for use. Establish and control password access.
- Review security and control issues related to spreadsheet use. Train personnel to access spreadsheet directly from network drive.
- Maintain version control.
- Control and save electronic data files.
- Ensure back-up and recovery.
When you are ready to qualify the spreadsheet, develop a formal Qualification Protocol. Include items like the following:
- Spreadsheet Name: State the name of the spreadsheet. Obtain a spreadsheet number from QA
- Purpose: Describe the use of the spreadsheet.
- Spreadsheet Owner: Identify the owner of the spreadsheet
- Responsibilities: Include the spreadsheet owner, the user and QA as the parties responsible for the spreadsheet including version control.
- Software Functions: Define the functions of the software: Identify manually input cells; identify software formulas; specify the expected outputs
- Test Plan: Define the test plan. Test at least three sets of test values for each formula:
- Describe the functions to be tested.
- Ensure that the test plan adequately tests security of the spreadsheet.
- Specify each step to be performed.
- Specify the equipment and methods to be used.
- Deviations, Exceptional Conditions, and Corrective Actions: Include form to document deviations, exceptional conditions and corrective actions observed during spreadsheet qualification.
- Acceptance Criteria: Include a list of the acceptance criteria.
- Approval: Identify who will review and approve the Protocol
- Spreadsheet Owner
- Department Director
- Quality Assurance
Prepare and approve a formal report. Include a copy of the spreadsheet with the executed data information and a copy of the hand calculations.
MWA can assist you with your software validation needs. Contact us for more information.