How GLNs Are Used in DSCSA & EPCIS: Why Every Pharmacy Needs Accurate Location Data

As Drug Supply Chain Security Act (DSCSA) interoperability takes full effect, Global Location Numbers (GLNs) have become essential for accurate EPCIS data exchange and verifiable chain-of-custody records. GLNs identify where events occur, who is responsible for a shipment, and which trading partners are involved in serialized transactions.

This post explores how GLNs function inside EPCIS events, how they support DSCSA compliance, and why pharmacies need them for both dispensing and distribution activities.

How GLNs Are Used in DSCSA & EPCIS

Where GLNs Appear in EPCIS

Every Electronic Product Code Information Services (EPCIS) event must identify the physical and business locations involved. GLNs appear in:

• readPoint – the physical location where the event (scan, shipment, receipt) occurred

• bizLocation – the business entity responsible for the event

Commissioning, shipping, receiving, packing, and decommissioning events all depend on GLNs to ensure trading partners can link physical movements to compliance records.

BizLocation vs. readPoint

Although both fields use GLNs, they serve different purposes:

readPoint

• The exact physical point where the action occurred

• Examples: receiving dock, scanning station, shipping lane

bizLocation

• The business unit or location responsible for the event

• Examples: the pharmacy, warehouse, or distribution center

Correctly assigning GLNs to these fields is crucial for preventing EPCIS mismatches and ensuring DSCSA compliance.

GLNs in TI/TS Data

Even as EPCIS becomes the standard for serialized data exchange, DSCSA’s Transaction Information (TI) and Transaction Statement (TS) still rely on GLNs to identify:

• Who sent the product

• Who received it

• The legal and physical locations tied to the transaction

Incomplete or incorrect GLNs in TI/TS records create regulatory gaps and complicate audits.

Identifying Trading Partners

DSCSA requires pharmacies and other entities to transact only with authorized trading partners. GLNs help confirm:

• Whether the sender and receiver are valid DSCSA trading partners

• Whether EPCIS data aligns with licensing and location records

• Whether serialized events match the businesses involved

A GLN functions like a universally understood ID number, removing ambiguity in compliance records.

Traceability and Auditability

GLNs make serialized traceability possible by establishing a clear trail of:

• Where a product moved

• When ownership changed

• Which entity is responsible for each action

During audits, regulators depend on GLNs to verify the accuracy and completeness of DSCSA data. Missing or misused GLNs can break the traceability chain and trigger compliance findings.

Why Pharmacies Need GLNs

GLNs in Dispensing vs. Distribution

Dispensing

Pharmacies use GLNs to validate inbound EPCIS data from wholesalers and manufacturers so that they can be dispensed.  

Correct GLNs ensure that serialized products are shipped to the correct location and recorded accurately in compliance systems.

Distribution

Any outbound transfer — including Loan & Borrow, inter-store replenishment, clinic supply, or emergency transfers (unless within the same legal ownership) — requires outbound EPCIS.

Outbound EPCIS cannot be generated without:

• A legal entity GLN

• A physical location GLN

This makes GLNs essential not just for receiving product, but for any pharmacy engaging in distribution activities.

Regulatory Expectations Under DSCSA

Regulators expect pharmacies to:

• Maintain accurate GLNs for all active locations

• Use GLNs consistently in inbound and outbound EPCIS files

• Match GLNs to licensed addresses on state and federal records

• Provide GLN-linked data during audits or investigations

Incorrect GLNs are treated as compliance gaps within DSCSA traceability.

GLNs for Trading Partner Identification

GLNs allow pharmacies and their partners to identify each other with precision in:

• EPCIS file exchange

• TI/TS data

• Exception handling

• Investigations and recalls

• Chain-of-custody verification

Using GLNs properly reduces misalignment between partners and prevents EPCIS rejection events—one of the most common issues in DSCSA compliance today—and the quarantine that results.

Summary

GLNs are the backbone of DSCSA compliance. They identify the physical and business locations involved in serialized events, support EPCIS accuracy, validate trading partners, and ensure pharmacies maintain a complete chain-of-custody record. Whether receiving or distributing regulated product, pharmacies must implement and correctly apply GLNs to remain compliant in the modern, interoperable drug supply chain.

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Want to learn more about GLNs? Explore the related articles in our blog series to dive deeper into how GLNs work, why they matter, and how they’re used across the supply chain.

• Introduction to GLNs: The Foundation of Global Track-and-Trace, DSCSA Compliance, and EPCIS Data Exchange

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