When peptide test results disagree, first confirm that they describe the same material, lot, measurement and basis. Then ask what changed between the tests and which evidence explains the difference.
Match the comparison first
| Field | Check |
|---|---|
| Material and lot | Same defined identity and linked sample history |
| Measured property | Content, purity and identity kept separate |
| Units and basis | For example, mg per vial versus mg per mL |
| Method and reference | Comparable measurement and calibration basis |
| Criteria and decision rule | Applicable limits, rounding and uncertainty |
Out of specification means outside established criteria. In an illustrative inclusive range of 9.0–11.0 mg, 8.6 mg is outside and 9.2 mg is inside. Those invented limits do not define a Novum specification. A passing 9.2 mg result can still differ from earlier observations; the pass label alone does not explain the change.FDA OOS investigation guidance (opens in a new tab)ICH Q6A specification definitions (opens in a new tab)
Name what the follow-up changed
| Activity | What changed |
|---|---|
| Reinjection | Another instrument reading from the existing laboratory sample |
| Fresh laboratory subsample | Another analytical sample from the same original unit |
| New vial | A different physical unit |
| Retained versus returned material | Potentially different custody and storage histories |
A changed result may reflect material variation, measurement differences or an established error. Ask for the evidence distinguishing those possibilities. A hypothesis should remain a hypothesis until the investigation supports it. Repeating a test or averaging a passing and failing value does not itself explain the discrepancy.FDA OOS investigation guidance (opens in a new tab)
Keep the evidence and unresolved points
Ask which original result remains valid, what the follow-up actually examined and whether an amended report was issued. Keep the original findings, the documented reason for any revision and any unexplained difference together.FDA OOS investigation guidance (opens in a new tab)
This is a report-reading checklist, not a statement that Novum operates a particular investigation or retained-sample programme. The available evidence may leave a discrepancy unresolved.FDA OOS investigation guidance (opens in a new tab)
Sources and further detail
- FDA — Out-of-specification result investigations (2022) (opens in a new tab)
General definitions and investigative principles; no product-specific procedure or compliance claim.
- ICH Q6A — Specifications and acceptance criteria (opens in a new tab)
Specification definitions and general decision reasoning only; no Novum limits assigned.
Revised from the existing source dossier on 3 October 2026. Supplied-report values are document transcriptions, not independent authentication or new measurements. Source notes identify the scope of each reference; this article has not undergone independent scientific peer review.