What needs to be clarified
Establish which stain properties were actually examined, separate screening, confirmatory and genetic findings, and compare the report's wording with the tests performed and their controls.
Materials to prepare
- Item bearing the marked stain and an available untreated adjacent area
- Reaction records showing controls, sequence and sampling locations
- Report with stain photographs and results of subsequent examinations
What to compare
Determine which reaction was used and whether the laboratory method treats it as presumptive or confirmatory. Review positive and negative controls, coloured fabric and prior treatments. Compare sampling locations across tests, distinguishing DNA detection from fluid identification and from establishing human origin.
Possible outcome of the analysis
A review may explain each test's evidential meaning, refine the wording of observations, map examined areas and identify questions requiring a separate confirmatory method.
Limits of the conclusions
A presumptive reaction establishes neither donor, age nor circumstances of deposition. Documentary review does not replace laboratory identification of the material or determine its transfer mechanism.