• Explain how science and medicine reached their current understanding of what is a “reference” and what is considered “normal”

normal changes between patients there is no textbook normal as everyone has variation known as genetic diversity. however doctors like to pick a reference range there is a set textbook definition and a slight lee-way across each side of it.

a reference is the set middle point

• Define what is meant by “norm referencing”, “reference intervals”, “reference limit”, “reference range” and “clinical decision limits”

norm referencing - Norm-referenced refers to standardized tests that are designed to compare and rank test takers in relation to one another

reference intervals - The reference interval for a given test is based on the results that are seen in 95% of the healthy population.

reference limits - the limit where a reference interval ends and another starts e.g. - the most widely distributed O2 levels that is most common in the population 95-99% whereas a reference limit for that reference limit would be 95% as it is the limit at which it is put.

reference range - based on the 95% healthy population this range is the reference range in which you can take a reference from

clinical decision limits - CDLs are based on the diagnostic question and are obtained from specific clinical studies to define the probability of the presence of a certain disease or a different outcome . These limits lead to the decision that individuals with values above or below the decision limit should be treated differently

• Explain how to apply the principles of Bayesian thinking to recalibrate the “reference” or “normal” in your clinical and scientific reasoning

We act on what we know, (on our understanding of normal) but what if we get new data?

is it a horse or a zebra type thinking, so someone may have a pain in their chest and we think heart attack but once that is ruled out what other things might it be? that maybe aren’t as commonly seen??? or maybe it is something as minor as indigestion however we won’t know but it was best to get the elephant out of the room before investigating niche issues.