A Basic Guide To Annotated CRF SDTM

If you deal with medical research and clinical trials, you may already be familiar with CRF and SDTM data collection and standards. Still, you might not know how they can work together to streamline your clinical data collection. The key is in the annotation.

When you annotate a case report form (CRF), it becomes a powerful tool for developing the metadata that'll go on to populate your study data tabulation model (SDTM) datasets.

A Basic Guide To Annotated CRF SDTM

This article will teach the basics of CRF SDTMs and why CRF annotations are so crucial for your clinical research.

What Is A CRF?

A case report form or CRF is used to collect the clinical data during a study. It can be a paper-based or electronic form developed by the sponsor company to capture the study data. The primary use of CRF is that it acts as a source document for the clinical study. All the details, such as a patient's diagnosis, lab test results, and treatment progress, are documented using this form.

What Is A SDTM?

The study data tabulation model (SDTM) is the industry standard for organizing clinical trial data for regulatory submissions. It consists of a set of standards and criteria by which to store and assemble data. SDTM can be used in or together with legacy systems, enabling you to simplify much of the process.

SDTM provides consistency, flexibility, extensibility, and structure to clinical trial data collection. As a result, it requires less time and fewer resources to transform your data into a submission-ready format.

Why Have A CRF and SDTM Annotated Together?

It's easy to see why CRFs and SDTMs are created separately. Both documents, after all, have their own sets of uses. This may be why some teams keep them in separate repositories.

However, it's better to annotate the CRF and SDTM together because the annotations provide a translator between the two documents at different levels of abstraction. In other words, the annotated CRF SDTM bridges any gaps between clinical data collection and data management that may otherwise result in confusion or misinterpretation.

A clear example is if there are discrepancies in how values are captured on a case report form and how they appear in the dataset specifications document (i.e., SDTM). In such instances, an annotated CRF serves as a reference guide that clarifies any ambiguities.

What Does CRF SDTM Do?

One of the biggest tasks in clinical research is collecting, processing, and presenting data from research participants. The CRF SDTM is a standard that aids in these endeavours by providing a universal, standardized format for organizing all this data.

The CRF SDTM allows you to:

  • Collect relevant information on subjects enrolled in your study
  • Create a database of subject trial-related data
  • Ensure quality control during data analysis
  • Analyze data faster and more easily
  • Easily prepare final reports

How Can You Implement An Annotated CRF SDTM?

Once you've defined all the data that your contract research organization (CRO) will be collecting in a clinical study, the next step is to design a case report form (CRF). A CRF is a form that clinicians complete for each patient enrolled in a clinical trial.

How Can You Implement An Annotated CRF SDTM?

An annotated CRF SDTM aims to allow for the quick and effortless transfer of data from the CRF into an industry-standard format. Doing so paves for faster analysis, more efficient integration with third-party tools, and more accessible data submission to regulatory authorities.

There are two best practices to follow when designing an annotated CRF SDTM:

1. The annotation should be done programmatically and thoroughly

If even one field's annotations are hand-coded, you are at risk of errors sneaking through if they aren't validated against your protocol or programmatically generated by the software. You must ensure that every field has been mapped to ensure no omissions in the transformation process.

2. Annotate using industry standards developed by CDISC

There may be other methods for annotating your CRFs, such as SDTMIG fields or user-defined fields. However, Clinical Data Interchange Standards Consortium (CDISC) standards are more universally accepted by regulatory agencies and tools vendors, making them safer to annotate with than other methods.

What Should You Consider When Annotating?

When annotating your CRF, you take every element of a high-quality SDTM dataset into account. The following should be checked:

All metadata

  • The CDASH/SDTM version number
  • The SDTM version number
  • The CDISC term identifier (CTI)
  • The CDISC submission value (SV)
  • All domains and variables (including those specific to your study features).
  • All controlled terminology (code lists) and classifications for each domain/variable


There's a lot on your plate when you're in a clinical trial. You're required to code and track the study protocol through machine learning tools, collect data through a CRF, and adhere to the FDA guidelines for safety reporting.

In addition to all this, you have to manage your daily tasks and continue following your patients with outstanding care. To make things simpler, you should consider an annotated standard for clinical data collection: The CRF SDTM.

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