Label Verification – Barcode & UDI Checks

This topic is part of the SG Systems Global manufacturing, logistics, and quality glossary.

Updated October 2025 • Product Identity & Compliance • GS1, UDI, EPCIS, Part 11

Label verification ensures that the machine- and human-readable data printed on unit, inner, and master pack labels are correct, scannable, and compliant for the destination market and channel. It goes beyond “did ink hit paper?” to confirm that the GTIN, lot/batch, serial, and dates match the work order; that symbologies (e.g., GS1-128, DataMatrix, QR) encode the right application identifiers and check digits; that human-readable interpretations (HRI) mirror the encoded values; and, for devices, that UDI carrier content is present and valid. In lean, regulated operations, label verification is a Jidoka-style stop: if a code fails verification, the system blocks release, captures evidence, and routes the exception through Deviation/NC and, if systemic, CAPA. Robust verification prevents wrong-SKU shipments, UDI nonconformances, and traceability gaps that frustrate recalls and customer scanning.

“A label isn’t compliant because it looks right—it’s compliant because every character, symbology, and link to master data is proven right before the product moves.”

1) What It Is

Label verification is the set of controls that prove labels are the right labels for the job ticket, route, and destination. It spans pre-press (template control and claim approvals), in-press (data binding, symbology rules, and checksum logic), and post-press (grade and content validation on the applied label). It is distinct from label inspection, which focuses on defects like smears, voids, or misplacement; verification proves the data are accurate and encoded correctly. In practice, both are combined at the station using smart scanners and machine vision, with logic embedded in MES/WMS so that the line cannot advance with unverified or mismatched identifiers.

2) Regulatory & Commercial Anchors

For medical devices, 21 CFR Part 830 defines UDI structure and issuing agencies; device history and distribution records integrate labels into the DHR. For foods and CPG, brand and retail mandates rely on GS1 system identifiers (GTIN, lot, date, serial) and application identifiers that power receiving, traceability, and returns. Where electronic records are used, Part 11 expectations apply to label masters, approval, print events, and verification logs. Downstream, EPCIS events depend on accurate identifiers; upstream, item masters and claims live under Labeling Control so SKU changes propagate with governance. The business drivers are equally strong: ASN accuracy, DC scan rates, UDI database synchronization, and fewer chargebacks.

3) Data Structures & Symbologies You Must Get Right

GS1 identifiers: GTIN (AI 01), lot/batch (AI 10), serial (AI 21), dates (AIs 11/15/17), count (AI 37), and variable measures when applicable. UDI: Device Identifier (static) plus Production Identifiers (lot, serial, manufacture/expiry, software version). Carrier choices: GS1-128 for cases and pallets; GS1 DataMatrix or QR for small items; linear EAN/UPC for retail-facing units. Checksum and quiet zones: Every barcode requires correct check digits and sufficient quiet zones to be gradeable. HRI: Human-readable text must mirror encoded values to support exception handling when a scanner fails or a customer requests manual confirmation.

4) Print Quality vs. Data Validity

Verification spans two dimensions. Print quality asks: can typical scanners decode the symbol? It depends on contrast, edge acuity, modulation, and defects like voids. Data validity asks: once decoded, do the values match the order, materials, and regulatory structure? World-class lines measure both. A label can look sharp and still fail if the GTIN is wrong for the SKU or the AI order is malformed; conversely, a correct payload is useless if grading fails and customers cannot scan.

5) Inline Verification Methods That Work at Line Speed

1) Triggered decode at print/apply: A fixed-mount scanner reads the just-printed code before application. The MES compares payload to the active work step and template version. On mismatch, the applicator halts and the label is rejected.

2) Post-apply machine vision: A camera verifies presence, position, rotation, and re-reads the code through glare and curvature. It checks HRI vs. decoded values and can confirm variable fields (expiry) against time-of-print rules.

3) Random sampling with verifier: For carton/case coding where 100% inline read is impractical, operators pull samples to a barcode verifier that reports a grade. The result is recorded to the lot’s eBMR and alerts when grades trend down.

4) Scan-back at ship: WMS requires a final scan at palletization and shipping. Payloads are checked against the shipment record and ASN; any anomalies open a hold on the shipment and route investigation before carrier pickup.

6) Master Data, Templates & Change Control

Mislabels are often master-data problems masquerading as print errors. Templates for every packaging level live under Labeling Control with versioning, claim approvals, and language variants. Each template binds fields to authoritative sources: item master for GTIN and description; MES for lot/serial; time service for dates; QMS for claim statements. Edits route through Change Control with impact assessment on customers and regulators. At runtime, printers receive variable data from the execution context—not from operator key-entry—so the line can only print what the order and status allow.

7) Exceptions, Holds & Rework Paths

When verification fails, containment is immediate. The station stops; the affected unit, case, or pallet is segregated with a printed hold tag tied to the job/lot; and the system records the raw image or scan payload, device ID, and failure reason. Deviation/NC flows capture root cause (template mismatch, ribbon wear, wrong data source, operator bypass). Rework steps are controlled: relabel after removal/obliteration, or scrap if removal risks product integrity. For serialized items, rework must maintain uniqueness—voiding and reissuing serials with full trace captured into genealogy and outbound EPCIS events.

8) How Verification Ties Into MES, WMS & QMS

In the MES, each packaging step defines required label types and validation rules. The eMMR specifies the template version; the runtime job enforces it; connected scanners publish decodes back to the step data. In the WMS, Barcode Validation on pick/pack verifies identity and prevents right-part/wrong-lot errors. In the QMS, template control, training, and audits live under Document Control; deviations and CAPAs close the loop when patterns emerge. All records, images, and payloads are time-synchronized with audit trails and electronic signatures as required by Part 11.

9) Station Design & Human Factors

High first-pass verification depends on ergonomics: lighting that minimizes glare; guides that align labels on curved surfaces; and scanners with feedback (beep/LED/tactile) audible over line noise. The HMI should show the expected payload next to the scanned payload with differences highlighted. Critical actions—like switching SKU or date offset—use Dual Verification. Printers and ribbons have status interlocks; low-contrast warnings prompt pre-emptive maintenance. Where language variants exist, the template selection is driven by the order’s ship-to and channel, not operator choice.

10) Metrics That Prove Control

Track first-pass verification rate by station/SKU/shift, grade distributions for 1D/2D codes, template mismatch incidents, scanner/vision read rates, operator bypass attempts (blocked), ASN scan failures at customers, UDI submission rejects, and time-to-contain mislabel events. Trend by ribbon/ink lot and environment (temperature/humidity). Tie results to KPIs such as chargebacks avoided, release lead time, and complaint rate.

11) Common Failure Modes & How to Avoid Them

• Right label, wrong data source. Template pulls a stale GTIN. Fix: bind to a single item master and require Approval Workflow after master edits.
• Keyboard entry. Operators type dates or lots. Fix: eliminate key-entry; populate from MES/WMS context.
• Skipped HRI match. Barcode correct, text wrong. Fix: vision OCR check that HRI equals decoded values.
• Quiet zone violations. Codes too close to borders. Fix: locked template geometry with print-time previews.
• Ribbon/ink wear drift. Good in the morning, poor by afternoon. Fix: monitor grade trends and set preventive maintenance thresholds.
• Language/market mix-ups. Wrong claim set. Fix: drive template selection from ship-to/channel plus Labeling Control approvals.
• Serialization reuse. Rework prints duplicate serials. Fix: central serial allocator with void/reissue logic captured in genealogy.

12) How This Fits with V5

V5 by SG Systems Global operationalizes label verification. In V5 MES, packaging steps declare required label assets and validation rules; printers receive variable data directly from the active operation; fixed-mount scanners and vision systems stream payloads and images; and Jidoka logic blocks progression when scans fail. Exceptions auto-open Deviations/NCs with attachments and reason codes routed via Approval Workflow. In V5 WMS, Barcode Validation, FEFO/FIFO, and Directed Picking prevent identity errors before ship; pallet labels are verified at build and scan-back at dock. In V5 QMS, templates and claims live under Document Control with training acknowledgments and periodic review. All events are Part 11 aligned and feed EPCIS and genealogy so external partners and auditors see one version of the truth.

Related Reading
• Identity & Standards: GS1 GTIN | EPCIS Traceability Standard | 21 CFR Part 830 (UDI)
• Execution & Proof: Barcode Validation | Labeling Control | eMMR | eBMR | Audit Trail (GxP)
• Regulatory Context: 21 CFR Part 11 | 21 CFR Part 101 | Device History Record (DHR) | Batch/Finished Goods Release