An Easy Guide to Reviewing SEND v4.0

SEND Implementation Guide v4.0 is the biggest change I’ve seen to the standard in the 15 years I’ve been involved. Here's what you need to know.

SEND 4.0 is almost upon us. Here’s why you will want to review it, and what you need to know to make your review as efficient as possible!

The latest version is about to be released for public review, and this is our chance to really understand what’s changing—and, just as importantly, to comment on it. It’s expected there’ll only be a single public review window, so this is likely the only opportunity we’ll have to influence changes we’ll all eventually need to adopt. Some of these updates could affect how data are recorded and the systems used to manage them, so I’d strongly recommend reviewing the document to make sure your data can be represented as intended.

SEND Implementation Guide v4.0 is, without question, the biggest change I’ve seen to the standard in the 15(ish) years I’ve been involved. The scale of change really shouldn’t be underestimated. The scope of data is expanding significantly, with more study types and results being standardized, and almost all existing SEND domains are changing too. That means major knock-on effects for data we’ve been producing in SEND for years.

While I’d always encourage a full cover-to-cover read, I know time is often limited. So below is a quick guide to the scope of the changes, to help you focus on the areas most likely to impact your organisation. I’d suggest starting there, identifying what matters most to you, and then diving deeper into those sections.

‘til next time,

-Marc

Overview of scope of the most significant changes:

What’s changing

1. Immune System Data Standardisation

We have introduction of new domains to support immunogenicity and immune cell characterisation.

Key changes

  • New Immunogenicity Specimen (IS) domain for antigen‑specific immune responses.
  • New Cell Phenotyping (CP) domain for characterisation of immune cell populations.
  • Expanded use of LB for immune mediators (e.g. cytokines, complement).
  • Clear decision logic on how immune data flows across LB, IS, and CP.

Impact

  • Enables standardisation of data types previously submitted in non-standard formats.
  • Significant impact for organisations running immunology, biologics, vaccines, or cell‑based assays.

2. New Findings Domains (Expanded Test Coverage)

2.1 Nervous System Tests (NV)

What’s changing

New NV domain for neurological and neurobehavioral assessments.

Includes

Functional Observational Battery (FOB), Motor activity, coordination, reflexes, sensory function etc

Impact

Expands the standardisation of safety pharmacology to include CNS test.

2.2 Skin Test Results (SK)

What’s changing

New SK domain for dermal irritation and skin-related assessments.

Includes

Quantitative (e.g. wheal diameter) and qualitative (e.g. erythema, edema) results.

Notes

Studies where the same‑subject is both treated and its own control, remain out of scope.

2.3 Ophthalmic Evaluations (OE)

What’s changing

New OE domain for ophthalmic examinations beyond routine clinical signs.

Includes

Pupillometry, tonometry, specialized eye exams.

Notes

Routine eye observations remain in CL.
Studies where the same‑subject is both treated and its own control, remain out of scope.

2.4 Pharmacokinetic Input (PI) Domain

What’s changing

New PI domain introduced between PC and PP.

Purpose

Stores adjusted concentration values used to derive PK parameters, including:

  • Omits values not included in the analysis
  • Replaces BLQ / ALQ text with substitute values

Impact

Major conceptual shift in how TK/PK derivations are represented.
May requires changes to PK workflows and reporting.

2.5 Scoring Scales (SX)

What’s changing

New SX domain to fully describe scoring scales used across findings domains.

Key rule

If a scoring scale is used, the entire scale must be represented in SX, even if results use controlled terminology.

Impact

Improves interpretability but requires additional dataset generation and linkage.

3. Updates to existing domains

3.1 Exposure Domain (EX) Updates

What’s changing

Multiple new EX variables added:
EXGRPID, EXOCCUR, EXREASOC, EXLAT, EXDIR, EXFAST
EXDOSFRQ removed.

Clear requirement to include:

  • Missed doses
  • All planned administrations
  • Non-occurrences

Impact

Structural changes to dosing data representation.

3.2 Microscopic Findings (MI) Expansion

What’s changing

Expanded scope to include:

  • Carcinogenic studies
  • Sexual maturity
  • Reproductive cycle phase
  • Targeted staining
  • Follow-up macroscopic examination

Controlled terminology additions:

  • Sexual maturity status
  • Reproductive cycle phase
  • Result modifiers, specimen condition, methods

3.3 Baseline & Timing Changes

What’s changing

Baseline flag (–BLFL) removed

Improved baseline interpretation via:

  • New variables across findings domains
  • Explicit inclusion of study phase elements
  • Improved representation for studies with multiple baselines (e.g. Latin square studies)

3.4 Domain Deprecations & Removals

What’s changing

Deprecated domains:

  • Tumor Findings (TF)
  • Body Weight Gain (BG)

3.5 Age Representation Changes

What’s changing

Move from text-based age ranges (AGETXT) to structured numeric values to improve precision and cross-study analysis.

4. Other Domains

4.1 Non-Standard Variables (NS)

What’s changing

SUPP– domains replaced with NS.

Looking for help with SEND? At Instem we offer both SEND software as well as SEND services providing conversion, conformance checks, and much more.

To learn more or request additional information about these solutions, simply contact us here.

Marc Ellison

Marc Ellison is the Director of SEND Solutions at Instem and has been a CDISC volunteer for 12 years. He has 3 decades of experience creating nonclinical software and working with researchers on how to best collect and organize their data. Marc refers to himself as a “SEND nerd” and is truly passionate about the concepts, debates, and evolutions around the SEND standard. Being a strong advocate for the importance of SEND in accelerating research, Marc launched his own educational blog at Instem called “Sensible SEND” to help educate and prepare researchers with cutting-edge details and explanations about the ever-developing process.

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