Problem: Consumable Traceability Gaps in IVD Supply Chains
A 2024 PATH survey of 340 primary care facilities in sub-Saharan Africa found that 23% received consumables with broken cold-chain seals, 11% received products past expiry, and 6% received suspected counterfeit cartridges identified only when assay performance failed. The root cause is the absence of automated, tamper-evident traceability at the unit level. Traditional approaches — paper-based batch logs, manual temperature excursion forms — rely on human compliance and provide no real-time visibility.
RFID Tag Design & Integration
Each diagnostic disc is injection-over-moulded with a 12 mm × 8 mm passive HF RFID inlay (ISO 15693, 13.56 MHz) embedded 0.6 mm below the disc surface. The inlay contains a 2 kB EEPROM storing: disc manufacturing batch, QC lot number, expiry date, reagent fill volume validation (optical check at manufacture), and a 256-bit ED25519 digital signature of all static fields signed by the BiQadx Manufacturing CA. The EtherX analyser reads the tag during disc insertion via an embedded planar antenna coil, verifying the signature before accepting the disc — rejecting any unsigned or tampered disc with a UI error state and audit log entry.
Environmental Monitoring — Embedded NFC Temperature Logger
A second tag type — an ST Microelectronics ST25DV-I2C dynamic NFC tag with integrated temperature sensor — is included in the foil packaging pouch. It logs temperature every 15 minutes (5-year log capacity: 175,200 readings) with ±0.3°C accuracy across −20°C to +70°C. Upon opening the pouch, the Dr. POCT instrument reads the temperature log and evaluates excursion events against the product's thermal stability profile (stored in the tag and cross-verified against the BiQadx product registry API). Excursion events trigger a conditional use flag — the instrument still permits testing but displays a 'thermal excursion recorded' warning, flagging the result in the LIMS with reduced confidence level.
Field Validation Results — Kenya & Bangladesh
Deployed across 35 facilities (21 Kenya + 14 Bangladesh) over 6 months. RF read success rate: 99.8% (4,221/4,230 insertion events, 9 failures attributable to physical damage to disc surface). No counterfeit discs detected (ED25519 verification 100% pass rate for authentic products). 127 cold-chain excursion events logged — 22 exceeded the 72h thermal tolerance threshold and were flagged as 'conditional use'; subsequent QC testing of these lots confirmed activity decline in 7/22 (32%) — validating the excursion threshold conservatism. Supply chain waste reduction: automated expiry flagging prevented use of 63 expired cartridge lots that would previously have been used without detection.