Glossary · Randomisation and supplyUpdated September 28, 2026

What is IRT (IWRS) in clinical trials?

Interactive response technology (IRT) is the system a trial uses to randomise participants, assign investigational product kits, manage site drug supply and support emergency unblinding. IWRS and IVRS are older names for the web and phone versions; RTSM is a common synonym.

  • IRT in plain language
  • How it works in practice
  • Related terms

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Dispense IMP · Week 4
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K-10418B-2207 · exp 03-2027
K-10419B-2207 · exp 03-2027
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In short

  • IVRS (voice) and IWRS (web) were the original forms; IRT is the umbrella term, and RTSM (randomisation and trial supply management) describes what it does.
  • Core functions: randomisation, kit assignment at dispensing visits, inventory and resupply to sites, expiry management and emergency unblinding.
  • Traditionally a separate system from EDC, integrated by data transfer. Unified platforms run both in one system with one audit trail.
  • Because it holds the allocation, IRT is central to maintaining the blind.

Explained

What IRT does across a trial

At enrolment, the site requests randomisation and IRT allocates the participant to an arm according to the randomisation list or algorithm, including any stratification. At each dispensing visit it tells the site which kit number to give, without revealing what the kit contains. Behind the scenes it tracks inventory at each site, triggers resupply shipments when stock falls below thresholds, and prevents expired kits from being dispensed.

When a participant's treatment must be known urgently for safety, IRT provides controlled emergency unblinding, recording who unblinded, when and why. Because every allocation and dispensing event is recorded, it also supports drug accountability and reconciliation at the end of the study. See IMP inventory and drug accountability.

In Capture

Randomisation and supply in the same system as the data

Capture runs randomisation at enrolment and kit dispensing, inventory and shipments in the same platform as the eCRF, with one audit trail. Blinded roles see no allocation information, and emergency unblinding is controlled and logged.

  • Randomisation with block size and stratification.
  • Kit dispensing and shipment receipt.
  • Emergency unblinding with an audit record.
RTSM software for clinical trials

Kit K-10418 · custody history

  1. At depotAvailable
  2. In transitAvailable
  3. At siteAssigned
  4. With patientDispensed
  5. ReturnedReturned (used)
  6. DestroyedDestroyed

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FAQ

Common questions

Something not covered here? Ask us directly.

What does IRT stand for?

Interactive response technology.

Is IRT the same as IWRS?

IWRS (interactive web response system) is a web-based form of IRT. IRT is the broader term, and RTSM is often used interchangeably.

Why is IRT separate from EDC?

Historically they came from different vendors. Unified platforms now run both, avoiding integrations and reconciling data in one audit trail.

How does IRT protect the blind?

It assigns kits by number without revealing contents to blinded users, and controls and logs any unblinding.

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