When the Label and the Tube Disagree

Part of Clinical Laboratory (LAB) Training: Sample Receipt and Identity.

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

The most common real-world problem

Labels come off. Labels get applied to the wrong tube. Two tubes arrive with one label between them. Handwriting is unreadable.

None of these are rare, and all of them are resolvable if you stop early.

Stop before you process

The instinct is to sort it out and keep the run moving. Resist it.

Once a sample is spun, aliquoted or frozen, the evidence that would have resolved the question is gone. The tube type, the fill level, the cap color and the position in the rack are all information, and processing destroys them.

Quarantine first. Investigate second.

Describe, do not interpret

Write what is physically true. "Two lavender-top tubes received, one bearing label for participant 0104, one unlabeled." That is a usable record.

"Tubes probably mixed up at the site" is an interpretation. It may be right, and it is not what you observed. Interpretations in a log become facts to whoever reads them later.

Who resolves it

The site team, not you. They hold the source documents and they know which participant was present.

Your job is to preserve the sample in a state where their answer can be applied, and to record the question clearly enough that they can answer it.

Document the resolution too

An unresolved query in a log is worse than no query, because it shows a known problem that nobody closed.

Record who confirmed the identity, when, and on what basis. "Confirmed by site coordinator against the visit schedule and source notes" is evidence. "Confirmed verbally" is thin.

When it cannot be resolved

Sometimes identity genuinely cannot be established. Then the sample is not used.

That feels like a waste, and it is the correct outcome. A sample with uncertain attribution that enters the dataset is worse than a missing one, because a missing sample is visible and a wrong one is not.

Report it as a deviation so the sponsor can assess the impact on the endpoint.