Concept

Failure response

A QC failure triggers a diagnostic first — the diagnostic determines the re-assay scope, not the other way round.

The escalation ladder (Bishi)

  1. Check the field first — was a routine sample transposed with a QC sample? Audit trail before chemistry.
  2. Check data entry — logs, sample register, lab tickets.
  3. Only then assume the lab. Re-assay pulps at the original lab with fresh same-type QC inserted in the re-run.
  4. Pass → accept. Fail → re-run. Third failure → send to a secondary accredited lab.

Scope: bracket by SAME-TYPE QC

The affected range runs from the previous passing QC sample of the same type to the next one — CRM failures bracket by CRMs, blank failures by blanks, ideally the same CRM code ("apples with apples"). Simón's dissent against over-scoping is the key nuance: a single random outlier affects only the outlier's neighbourhood — repeat the outliers plus neighbours to learn whether the error is random or systematic, and re-run the whole batch only if it proves systematic. Small batches (≤20 samples) exist precisely so problems can be ring-fenced.

Two rules that survive every convention

  • Failed values are retained, never overwritten. Keep the failed result, link the replacement, record the reason — the regulatory audit trail (NI 43-101 requires the corrective actions be reportable).
  • Timeliness is the #1 documented failure. "Storing the data… and not processing them on a timely fashion, or not processing them at all" is Simón's most-repeated finding. QC review is a gate before batch acceptance, not a report at resource time — late review has cost operators entire drill campaigns.

In geoDB

geoDB evaluates each certificate as it arrives — pass rates under 85% flag selective re-assay, under 70% flag the certificate for rejection — and the certificate approval flow is your acceptance gate. Re-assayed values are kept alongside originals rather than overwriting them. Same-type bracketing (which sample ranges a failure implicates) is not computed automatically; the certificate page's sequence charts are the manual tool for it.