Custody Is Who Held the Aliquot, Not Where the Box Sits

Sample chain of custody is a person-and-time trail for who held the aliquot. It is not a freezer map, and it is not a catalog of unopened lots. Prefer writing the person, the time, the aliquot ID, and the next holder. Reject a box diagram that still claims to be custody.

Sample tracking versus inventory software still owns aliquot history versus stock. Experiment-record traceability uses “chain of custody” for data and files. Shelf-to-record IDs still own stable identifiers. This page only defines physical possession. It does not choose inventory software. It does not follow a plasmid file through tools. It does not invent a legal statute.

Custody Is a Person-Time Trail

Sample chain of custody is the documented sequence of possession for one physical aliquot. Each event names who held it, when they took it, when they released it, and who received it next. The entity is the tube, vial, or plate well, not the experiment narrative and not the freezer coordinate. If a later reader cannot say who had the aliquot between two timestamps, custody is missing. Location may still be known. Those are different facts.

The search asks what sample chain of custody is. The short definition is possession, not geography. A freezer map answers “where.” Custody answers “who.” A lab can have a precise box map and still have no custody trail if anyone with a key can take a tube without writing a name. The reverse is also true: a signed handoff can exist while the box map is messy. Do not treat one as proof of the other.

What a Freezer Map Is Not Allowed to Mean

Score three objects on the same labels so the phrase stops sliding.

Prefer custody language only when a later dispute or assay depends on who touched the tube. Prefer a freezer map when the job is finding the box. Prefer an inventory record when the job is whether an unopened lot remains. Reject a sentence that calls the box map “the chain of custody.” That sentence is how a missing handoff hides inside a tidy diagram.

On-site pages already use the phrase for data lineage. That usage is common and confusing. Data lineage follows files, parameters, and edits. Physical custody follows the aliquot. If the question is which primer file informed the run, leave this page. If the question is who carried the lysate to the core, stay.

A Worked Custody Event

A worked event is one transfer, not a novel. Aliquot S-0142-A leaves the −80 box at 09:12 with Operator A. Operator A hands it to Operator B at 09:18 for a thaw. Operator B returns the remainder at 10:05 and writes the remaining volume. Each line has a person, a clock, and the same aliquot ID. The box coordinate can sit on the same form. It does not replace the names.

A worked fail is a core submission labeled with a freezer position and no courier. The position is true when the tube left. It is not evidence of who held it in the building. Another fail is a shared “sample checkout” spreadsheet that records only the date. A date without a person is a calendar, not custody. This example is an operational heuristic. It is not a cited legal form and not a promised evidentiary standard.

Record the Event After the Trail Is Named

Write the trail before anyone buys a custody badge. If the lab only needs to find boxes, stop. A custody product is not the subject. If the lab must reconstruct possession, name a record surface after the event fields exist. ZettaNote is one such surface: official product language includes structured experiment documentation. A dated entry can hold person, time, and aliquot ID. That is a place a custody event may be written. It is not a LIMS. It is not a chain-of-custody appliance. ZettaFile should not be treated as sample management. Golden Gate is not a Zetta feature and is irrelevant here.

If the group still calls the laminated box map “our custody,” you do not have a trail. You have geography. Write the person. Write the time. Then, if you also need the box, draw the box as a second fact.

Barcode scans can help and still fail this definition. A scan that only writes a new coordinate is a better freezer map. A scan that writes person, time, aliquot ID, and next holder is a custody event that happens to use a scanner. Do not let the word barcode stand in for the trail. The inventory-software page already owns whether a lab should buy scanning. This page only asks what the event must prove. A handwritten log that names people can be custody. A scanned move that names no person is still geography.

Legal and diagnostic labs attach extra forms, seals, and witness rules to the same phrase. Those rules are jurisdiction-specific. This page does not import them and does not claim Zetta satisfies them. Molecular biology groups often only need enough person-time detail to reconstruct who thawed a precious aliquot. Write that smaller trail honestly. Do not dress a box map in forensic language. If a later assay depends on whether the tube sat on a bench for two hours, the trail must include that interval. If it does not, say the interval is unknown. Unknown is a fact. A fake complete log is not.

Shared “checkout” boards fail in a third way. The board names the person who took the box, not the person who took the aliquot. A box can leave with six tubes and return with five. The board still looks complete. Custody is per aliquot, or at least per named subset that left together and came back together. If the subset changed, write the change. A missing tube that is later found in a different rack is a location problem and a custody problem. Fix both. Do not pick the easier diagram and call the job done.

Frequently Asked Questions

Is a freezer map the same thing as sample chain of custody?

No. A map shows location. Custody shows who held the aliquot. A tidy box can still hide an unnamed handoff.

Is sample chain of custody the same as experiment-record traceability?

No. That sibling follows data and files. This page follows the physical aliquot. A complete notebook can still miss who carried the tube.