Whose Sample Is This

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

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

Identity is the one error with no recovery

A processing error can sometimes be explained. A storage excursion can be assessed. A misidentified sample cannot be repaired by anything you do afterward.

If you cannot prove whose sample this is, the result cannot be used. Worse, if it is used and the attribution is wrong, it corrupts two participants' data at once.

Use two identifiers

The requisition and the label must agree on at least two independent identifiers. Usually the participant identifier and one of date of birth, initials or visit number.

One matching field is not enough. Sequential participant numbers differ by a single digit, and that is exactly the error you are guarding against.

Names are usually not the identifier

On most trials, the laboratory should not hold the participant's name. The study identifier is the identifier.

If a name arrives on a tube, that is itself a finding worth raising. It is a confidentiality issue as well as a labeling one.

The traps that catch careful people

Similar identifiers. Participant 0104 and 0140 on the same rack.

Sequential draws. Two participants seen back to back, labels printed together.

Pre-labeling. Tubes labeled at the bench before the draw, then filled in a different order.

Rescreened participants. The same person may hold two identifiers across screening periods. The second one is the live one.

What to do when identity is in doubt

Quarantine the sample. Do not process it. Processing destroys the ability to investigate.

Document exactly what you observed, in the words of what you saw rather than what you think happened.

Query the site team. They can check who was in the chair and at what time.

Only release the sample when the site confirms identity with a documented answer.

If two tubes carry the same label

Neither can be attributed. Both are quarantined until the site resolves it.

Choosing the one that looks right is the failure mode this rule exists to prevent.