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Specimen timing within a clinical process may matter when interpreting IVD performance. Samples from initial presentation, progression or follow-up can represent different questions. Define the target condition and its temporal context.
Define the assessment
Link presentation, symptom onset, diagnostic assessment and specimen collection according to the research question. Do not record unknown timing as an exact day. Effects are not identical for every assay; justify relevant characteristics through evidence and intended use.
Worked example
For example, specimens mainly come from later assessment, but intended use concerns initial presentation. The team does not transfer favourable performance directly to early use. It examines the number and clinical context of early specimens and discloses the missing interval. Authorised analytical decisions explain handling of uncertain dates.
Practical checks
- Map important clinical-event and specimen-time definitions in the data dictionary.
- Code exact dates, estimated intervals and unknown timing differently.
- Compare represented clinical periods with the intended-use period.
Decision and limitations
The report should show when the test was evaluated. Do not extend findings to every disease stage. Limited evidence at one stage does not automatically mean poor performance, but may limit inference. Link further data needs to that question, with qualified clinical interpretation.
Frequently asked questions
- Can an unknown onset date be filled by guesswork?
- If estimation is justified, preserve its estimated status rather than presenting it as exact source information.
- Does good performance at one stage cover every stage?
- No. Justify the relationship between intended use and represented intervals.