- Published
- Updated
Good separation between obvious cases and completely healthy people does not establish equivalent discrimination in uncertain presentations. The clinical spectrum in the sample determines where an IVD performance result can be interpreted.
Define the assessment
Describe symptom levels, disease stages and similar conditions in the intended-use population. Show how participants were selected. Convenient clear positives and clear negatives can answer development questions, but their limited scope should remain explicit.
Worked example
For example, development uses advanced cases and healthy donors, while intended use concerns early, uncertain symptoms. The team does not treat the initial separation result as target-population performance. It identifies the missing clinical range and plans evidence representing it, without excluding challenging samples merely to improve results.
Practical checks
- Compare important characteristics of the study sample and intended-use population.
- Explain inclusion of uncertain, mild and clinically similar presentations.
- Discuss how excluded groups affect the applicability of findings.
Decision and limitations
The report should describe the sample behind the performance number. Not every study must represent every clinical condition; justify its scope against the proposed claim. Avoid unconditional generalisation to unrepresented situations and carry limitations into the further evidence plan.
Frequently asked questions
- Are studies with obvious cases useless?
- No. They can answer specific questions but should not automatically support broader clinical-use claims.
- Are healthy controls always the right negative group?
- That depends on intended use. The real diagnostic question may involve other negative or similar conditions.