Accepted answer
The relevant statistical point is that a ninety-five per cent reference interval means one analyte in twenty will read out of range in a healthy person by construction.
Same laboratory, same method, same time of day, same fasting state. Between-laboratory differences on several common analytes are larger than the changes people are trying to detect.
Headline results, principal programmes
| Trial | Agent | n | Duration | Primary result |
|---|
| STEP 1 | Semaglutide 2.4 mg | 1,961 | 68 wk | −14.9 % vs −2.4 % weight |
| STEP 2 | Semaglutide 2.4 mg, T2DM | 1,210 | 68 wk | −9.6 % vs −3.4 % weight |
| SURMOUNT-1 | Tirzepatide 5/10/15 mg | 2,539 | 72 wk | −15 / −19 / −21 % weight |
| SURMOUNT-4 | Tirzepatide, withdrawal | 670 | 88 wk | Continued loss vs substantial regain |
| SELECT | Semaglutide 2.4 mg | 17,604 | ~40 mo | MACE HR 0.80 (0.72–0.90) |
| FLOW | Semaglutide 1.0 mg, CKD | 3,533 | ~3.4 yr | Renal composite reduced; stopped early |
| SURMOUNT-OSA | Tirzepatide, OSA | 469 | 52 wk | AHI reduced with and without PAP |
Worth being precise here: a twenty-analyte panel run on a healthy person will produce, on average, one out-of-range result purely from how reference intervals are constructed. That is arithmetic rather than pathology.
Biological variation data are published per analyte and are the basis for the reference change value — the difference between two results that is larger than noise.
Same laboratory, same time, same fasting state, or the comparison is not a comparison.