Cold Chain
Definition
The documented, unbroken sequence of temperature-controlled environments (refrigerated vehicle, controlled intake, laboratory refrigerator or freezer) through which perishable biological evidence passes from collection to analysis. A break occurs whenever evidence warms outside its required temperature range during any transfer.
- Applies to
- Perishable biological evidence
- Path
- Collection through refrigerated transport, intake, and lab storage
- Break condition
- Any warming outside the required range during transfer
- Requirement
- Documented, unbroken temperature control
Common questions
What happens to biological evidence if the cold chain is broken?+
Warming accelerates bacterial growth and enzymatic degradation, which can reduce DNA yield or quality, and a documented break gives opposing counsel grounds to challenge the reliability of any results obtained from that evidence, even if the material still tested successfully.
How is the cold chain documented for court purposes?+
Each transfer point logs the time, temperature or storage condition, and the person handling the evidence, so the full temperature history from scene to laboratory can be reconstructed and produced alongside the standard chain-of-custody paperwork.
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...
- Deoxyribonuclease (DNase)
- An enzyme that cleaves the phosphodiester bonds in the DNA backbone, fragmenting double-stranded DNA into shorter pieces. Bacteria and fungi produce extracellular...
- Paper Packaging
- The standard packaging material for biological evidence. Paper is gas-permeable: residual moisture evaporates through the packaging after sealing, preventing the humid microenvironment...
- Partial DNA Profile
- A DNA profile in which results were obtained at fewer loci than the full STR panel used. Partial profiles arise from degraded...
- Q10 Rule
- The empirical observation that most chemical and enzymatic reaction rates roughly double for every 10-degree Celsius increase in temperature. Applied to DNA...