Sample Handling, Chain of Custody & Retention

Samples are received at the goods-in bay (weekdays 09:00 – 17:00 HKT). On receipt, sample-receipt personnel:

• Photograph outer packaging, seals, and any evidence of tampering.
• Log arrival temperature (ambient samples inspected within 2 h; cold-chain within 30 min).
• Assign a ALS Sample Identifier (MSI) formatted MRD-YYYY-NNNNNN and generate a printed barcode label.
• Cross-check against the submission form for count, condition, and hazard declaration.
• Record a formal receipt record countersigned by two persons.

Every movement of a sample — between the receipt bay, storage, an analytical workstation, and disposal — is logged in the LIMS with a time-stamped hand-off between named individuals. All laboratory areas hold CCTV coverage retained for 30 days on the rolling loop. A tamper-evident chain-of-custody form is generated on request and delivered with the report.

Sub-sampling follows SOP LAB-014 (‘Aliquoting for LC/GC/ICP-MS’) with tared, calibrated balances (Mettler XSR205DU / MS205DU) and dedicated disposable spatulas. Sub-samples are labelled with the parent MSI plus a sub-index (e.g. MRD-2026-000123-A1) and reconciliation is checked at the end of each shift.

Where a result is contested, all remaining sample and sub-sample material, raw data, and instrument logs are quarantined until the appeal is resolved under QMS-045. Quarantine is invoked automatically by opening an appeal ticket.