Tuesday, 1 September 2009

How many items make a pack? part 2

Today I gave blood (it was, according to the records, my 66th time). The UK blood donation service collects a donation of 470ml. Why 470? I asked, being an Elephant's Child with insatiable curiosity (or "'satiable curtiosity" as Kipling wrote).

The service decided on 470 because it was found to be an amount that a healthy donor of minimum weight can safely give; if it were to be increased, then it would prevent some donors from giving. If it were reduced, then handling it (because each donation is divided into parts) might become difficult. So it is 470ml (or equivalent because it is weighed) for good reasons.

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