> Order of magnitude errors aren't that hard, it is improbable that a hospital will need to prescribe enough drugs for a small horse.

Weight range in children's hospitals ranges from 100s of grams to 100s of kilos - that's three orders of magnitude right there.

> Doctors seem to run too much on autopilot, they leave discretion to laboratories who give recommended ranges for various hormones/vitamins/chemicals in the blood.

Both population biochemistry and laboratory assays vary between hospitals and labs. So it's actually really important that we interpret biochemical results in relation to the normal ranges provided to us by the lab. Also, those normal ranges are not just set by the lab without thought, there are pathologists and clinical chemists involved in the process.

I think we think about these numbers a whole lot more than you think we think about them.