The sample knows where it came from
Fourteen sample types, each with its own path from the procedure to the result. The code is unique across the clinic, every state change carries a person and a time, and autologous fat knows two operations: the one it came out of and the one it went back into.
One code, issued once across the whole clinic
Every sample gets a code when it is created, built from the clinic's prefix, the short form of the sample type and a running number — PKK-HIST-0311, for instance. The code is unique across the whole clinic, and the prefix is set exactly once: as soon as the first sample exists, Viali locks it. That is strict on purpose. A prefix changed later would mean two containers in the fridge could carry the same number.
Fourteen types, and each has its own set of states
Histology, cytology, frozen section, microbiology, blood, bone marrow, stem cells, autologous fat, oocytes and sperm, DNA and genetics, stones, foreign bodies, placenta and cord — and «other» for the rest. A frozen section is processed and produces a result; a histology sample is sent away and the result comes back. Those are different paths, so each type carries its own states rather than one shared set that fits none of them properly.
Taken during one operation, returned during another
Autologous fat is taken during one procedure, stored, and put back months later during a second. Viali holds both operations against the same sample — the extraction and the reimplantation. Open the record and you can see where the material came from without paging through last year's theatre notes. Sample types where a return never happens do not show the field at all.
Every state change with a person, a time and a lab
A state change is appended, not overwritten. Each sample carries the full chain: who took it, who sent it, to which external lab, and when the result came back. That is the question that matters day to day — «where is the sample from three weeks ago» — and it is answered without anybody maintaining a second system.