Barcodes... Ever wondered how it works 4285

I must have come across them 25-30 years ago when I worked for the UK Health Service and was sent to rescue a project for the local Blood Transfusion Centre.

They were introducing bar codes on the blood collection packs, can't remember what coding was used, but each pack had a unique bar coded serial number with additional stickers for the sample tubes used for laboratory testing.

The collected (untested) packs arrived and went into a temporary storage area. The sample tubes were tested by an automated analyser (controlled by a PDP-8) and the results, originally printed on a tty, were captured by a PC (latest Z80 based) and stored on a floppy disc.

The floppy disc was taken to a second machine in the temporary storage area where the packs were sorted. The serial numbers were 'wanded' and the VDU showed the blood type. A second 'type' label was then affixed to the pack adjacent to the serial number and the complete label rescanned to check that the correct type label had been attached. The usable packs were then booked into the main storage area for issue.

As far as I remember, the coding on the serial number was an 'alpha' start followed by an 8 digit (may have been longer) serial number, then a 'delta' pause. On the 'type' label you had a 'delta' pause followed by a 3 (or 5?) digit type code, ending with a 'beta' stop. The type labels were also brightly coloured to very easily distinguish the blood type.

It was an interesting job, I had to work in the laboratory with the technicians to find what they needed and to work with the equipment. I also had to be given a crash course in blood typing-testing so that I understood the testing and how to interpret the results. his was in the days before HIV was known and virtually all testing was done with open test tubes-cells. I doubt very much that this is the case nowadays.