Laboratory reference ranges for hormones often represent the 10th to 90th percentile or two standard deviations from the mean.

“for some things like hormones you're often going to see you know between x and y and any lab will tell you upon asking they usually don't print this on the lab but we go back and usually ask them what do your reference ranges represent and it's usually either 10th to 20th percentile to 80s to 90 a--the percentile or two standard deviations below the mean to two standard deviations above the mean”