Sequential testing protocol
Definition
The standardised order in which biological stains are examined: presumptive test, then confirmatory test, then species confirmation, then typing and DNA analysis. Designed to answer each question using the minimum sample and the least destructive method before proceeding to the next stage.
Related terms
- Chain of custody
- The unbroken documentary trail of who held a sealed exhibit, when, and under what seal, from the moment of collection through analysis...
- 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 DNA extraction method used for sexual assault evidence that separates sperm cells from epithelial cells before cell lysis, yielding two DNA...
- Non-destructive examination
- Any examination that does not consume or significantly alter the stain: visual inspection, alternate light source (ALS) examination, photography, and microscopy of...
- PCR inhibitor
- A substance in a sample extract that suppresses the polymerase chain reaction, reducing amplification efficiency or causing amplification failure. Haemoglobin, melanin, humic...
Explained in
- Order of Testing and DNA PreservationThe standardised order in which biological stains are examined: presumptive test, then confirmatory test, then species confirmation, then typing and DNA analys...