# Failure response

> diagnose field→entry→lab before any re-assay

Source: https://geodb.io/guide/topic/qaqc_failure_response/ · Category: QAQC
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.