Non-Destructive Examination
Definition
Any examination that does not consume or significantly alter the stain: visual inspection, alternate light source (ALS) examination, photography, and microscopy of an intact surface. These are always performed before any chemical test.
Related terms
- Chain of Custody
- The documented chronological record of who collected, handled, transferred, and examined a piece of evidence. For digital evidence, chain of custody includes...
- Destructive Testing
- Any test that consumes, extracts, or chemically alters the stain material: cutting a fabric swatch, swabbing a surface, adding a chemical reagent....
- Differential Extraction
- A two-step DNA extraction procedure used when a stain contains both sperm cells and non-sperm epithelial cells. The first step lyses epithelial...
- PCR Inhibitor
- A co-extracted substance that interferes with Taq polymerase activity or primer annealing. Common inhibitors in forensic samples include haemoglobin (from blood on...
- Sequential Testing Protocol
- The standardised order in which biological stains are examined: presumptive test, then confirmatory test, then species confirmation, then typing and DNA analysis....
Explained in
- Order of Testing and DNA PreservationAny examination that does not consume or significantly alter the stain: visual inspection, alternate light source (ALS) examination, photography, and microscop...