Chain of Custody and Why Gaps Matter

Part of Clinical Laboratory (LAB) Training: Aliquoting, Labeling and Chain of Custody.

About 2 minutes. Free, in your language, no account needed.

Custody is a continuous claim

From receipt to shipment, the record should show where each sample was and who was responsible for it, without an unexplained interval.

A gap does not prove anything went wrong. It proves you cannot show that nothing did.

What a custody record holds

Who handled the sample, when, and what they did. Where it was stored between steps. When it moved, and to whom.

The test is whether a reader can follow the sample from the door to the shipping box without guessing.

Gaps are usually mundane

A sample sits in a rack while the technician goes to lunch. Nobody logs it because nothing happened.

That is exactly the interval an inspector asks about. The answer "it was in the rack" is fine when the record shows it went into the rack at a time and came out at a time.

Transfers between people

When a sample changes hands mid-process, both people should be identifiable in the record.

Shift handovers are the classic weak point. The sample was received on one shift and processed on the next, and the log shows only the second person.

Storage is part of custody

A sample in a freezer is still in your custody. Which freezer, which shelf, which box, which position.

"In the minus eighty" is not a location. When somebody needs that sample in two years, a box and position is the difference between five minutes and an afternoon.

Access matters too

Restricted access to storage is part of the claim. A freezer anyone can open weakens every custody statement that depends on it.

This is not about suspecting colleagues. It is that a documented, controlled access route is what makes the record mean something.

Why this is worth the effort

Custody is what converts a tube into evidence. Without it you have a sample that probably belongs to someone and was probably handled correctly.

Probably is not a standard a regulator accepts for a result that supports a marketing application.