Your Easy Guide to Clinical Studies

Callcualted Fields (CF) are programmed activities in the study database (eCRF) to convert data into a more useful format or needed information (e.g. age upon study start, BMI based on height and weight). CFs have an important advantage, as they are automatically processed and therefore exclude human calculation errors.

 

Required calculations can be done either when the data is entered in the study database (pre-processing) or after being exported (post-processing)

 

CFs require:

• An electronic database (e.g. CDMS)
• Ability to program calculations (e.g. formula, classification)
• Validation procedures to ensure automated processing was correctly implemented

 

Example

Calculation of creatinine clearance requires the input of raw data into an applicable formula (age, weight, serum creatinine, and gender). Upon automated data processing the creatinine clearance number is no longer raw data (e.g. source data) but automated processed data.

As a SP-INV, and based on data needed to answer your study question:

• Make a list of study data (variables) that can be obtained through automated processing

 

For pre-processing:

• Define which variables must be available
• Ask your data manager to program the required calculation(s) in the study database
• If needed, implement alerts for upper and lower calculation limits
• Include a test phase to guarantee that pre-processing calculations are correctly implemented. Document the implemented validation procedures

 

For post-processing:

• Define which variables must be available for data export (e.g. for analysis)
• Ask your data manager or statistician to program the required calculation(s) based on the raw data
• Include a test phase to guarantee that post-processing calculations are correctly implemented Document the implemented validation procedures

 

Describe any automated processing in the study protocol, DMP and/or SAP

References

ICH GCP E6(R2) – see in particular guideline

• 5.5 Trial management, data handling, and record-keeping