Probenkennzeichnung

Probenkennzeichnung is the step that connects a tube of blood to a name. It is the least interesting part of the appointment and the one with the worst failure mode, because a mislabelled sample does not produce an error message. It produces a plausible result filed under the wrong person, and nothing downstream can detect that. Every other part of Präanalytik can be repeated if it goes wrong. This one can be repeated only if somebody notices.

The rule that carries almost all of the safety is about place and time rather than content. The tube is labelled at the person, immediately after it has been filled, before the next tube is touched and before anything leaves the room. Not later at the bench, not once the customer has gone, not from memory while tidying up. Pre-labelling before the draw is the mirror image of the same error, because a labelled empty tube can be filled with the wrong blood. Identity is confirmed by asking the person to state their own name and date of birth rather than by reading a name to them for confirmation, since a person who is nervous will agree to almost anything.

What goes on the label is set by the laboratory rather than by the pharmacy. In practice it is the identifying data of the person, the collection date and time and the reference that ties the tube to the accompanying request, usually as a barcode issued with the request form. The label has to sit where the analyser and the laboratory staff expect it, which means it must not cover the fill mark or wrap so that the barcode cannot be read. The akkreditiertes Labor publishes its own requirement and that is the version that binds.

A tube that arrives unlabelled, illegibly labelled or carrying data that contradicts the request is not analysed. It is rejected, and correctly so, because the alternative is a laboratory guessing at identity. For the pharmacy that means a second appointment, a second draw and an awkward conversation. It is the cheapest error in the whole workflow to prevent, which is why the labelling step is written into the Standardarbeitsanweisung as its own point and checked again at handover to the Probenlogistik.