I gave blood this morning. The protocol the nurses use is incredibly precise.
There are no SHOULDs or MAYs here, everything they do is specified to the finest detail. Beyond the expected rigour over medical (and travel, Hong Kong gave them pause for thought) history, each operation is scripted out. The amount of time the nurse spends swabbing iodine before inserting the needle is even prescribed - and timed. I'm surprised the donut I had afterwards wasn't weighed to ensure I received the desired amount of sugar.