Inspired by this thread.
In the U.S. blood glucose is measured in milligrams per deciliter (mg/dL). In Canada, its measured in millimol per Liter (mmol/L). How did this come to be? It’s obviously not English vs Metric units or anything. Thanks!
In Canada, SI units are used (“Système International d’unités”). This represents a change from the traditional units of measurement, still used in the US, and took place in the mid-80’s IIRC.
Originally, every country was supposed to adopt them. For reasons of which I’m uncertain, the change never materialized in the US.
Personally, I actually prefer the old units if for no other reason that 1) a lot of rules of thumb were based on them and 2) I, and others, had developed an intuitive feel for them (and their related critical values) which had to be given up with the switch to SI.
Interesting, thanks! So does most of Europe use the SI units, as well, or are there some holdouts there, as well?
No cite, but I am almost certain that the US is the only holdout.
There is less adherence to the SI units for things like blood pressure. That’s a great example of where there is little gain in adopting them but a real loss in your intuitive feeling for what’s normal or not, e.g. Is a BP of 190/115 high? Sure, you know instantly if for no other reason than the diastolic being higher than 100.
OK, how about BP in SI units. Consider, BP = 25/17. Is that high? Low?