How do urinary metabolites correlate with serum levels?Updated 2 months ago

Serum labs and Mira measure related—but not identical—signals, so some divergence is expected and usually not concerning. Serum LH and FSH reflect a single time-point circulating concentration (a snapshot). Mira measures urinary LH and FSH, as well as urinary metabolites E3G (estradiol metabolite) and PdG (progesterone metabolite), which reflect renal excretion over the prior several hours (and for E3G/PdG, metabolism must occur first). 

As a result, urine results function more like a time-averaged, delayed reflection of serum dynamics rather than an instantaneous equivalent. In addition, serum and urine testing use different assays/units (and urine concentration can vary with hydration/timing), so values should not be expected to numerically match even when reflecting the same physiologic state. 

Research involving Mira shows a strong correlation in overall patterns between serum hormone dynamics and urinary measures (see research here), but not a 1:1 equivalence. (see research here). 
For clinical interpretation, it is most useful to evaluate trends over time and interpret results within their own reference ranges (serum vs urine), rather than comparing isolated data points across sample types. 
Many providers use Mira for longitudinal, cycle-based trend monitoring and reserve serum labs for targeted, time-specific decision-making when precise circulating levels are needed. Mira is a complement to serum testing, not a replacement.