Every lab a primary care doctor or GYN orders comes back against a standard reference range, the print-out most women have seen dozens of times with normal sitting quietly next to their number. That range is built from a population, not from you, and its job is to flag disease, not to describe what feels good. The Choosi Read reports every marker against that same standard range and against a second, narrower band we call optimal, because a woman can clear the first and still be nowhere near the second.
What a standard range is built to catch
A standard range, the number printed under normal on your results, comes from a statistical spread across a large population sample. It is wide by design, built to flag clear disease on either end while including everyone who falls in between, whether or not they feel well. TSH is a clean example. The standard range on most panels runs from 0.4 to 4.5 mIU/L, wide enough to rule hypothyroidism and hyperthyroidism in or out, but not built to describe where your energy, mood, and metabolism actually run best.
Ferritin follows the same shape. Most standard panels read anything above 10 ng/mL as normal, a bar low enough to catch outright anemia but nowhere near where most women stop feeling tired, cold, and foggy. The range is not wrong. It is just answering a narrower question than the one most women are actually asking.
What optimal means, and where the numbers come from
Optimal is a narrower band inside the standard range, the zone where a marker tends to sit in women who do not have the symptom it explains. On that same TSH panel, Dr. Hall reads for an optimal band of 0.5 to 2.0 mIU/L, less than half the width of the standard range. The optimal band for ferritin runs 70 to 150 ng/mL, not the 10 ng/mL floor a standard panel clears. Vitamin D, another marker most patients test low on, carries a standard range of 30 to 100 ng/mL and an optimal range of 50 to 80 ng/mL. The pattern holds across the panel. Optimal is not a stricter opinion layered onto normal. It is a different question, asked and answered against a narrower, function-focused range.
Where the gap becomes symptoms
This is where the gap stops being academic. Fasting insulin reads as normal anywhere from 2 to 25 uIU/mL on a standard panel, while the optimal range Dr. Hall reads for is 2 to 6 uIU/mL. A result of 14 clears the standard range with room to spare, and can still mean a pancreas working hard to hold glucose level, years before fasting glucose or HbA1c ever moves. TSH shows the same shape from the other direction. A result of 4.0 mIU/L sits inside the standard range but well above the 0.5 to 2.0 optimal band, and it is common for a woman with that exact number to be told her thyroid is fine while she still lives with the fatigue, weight change, and brain fog it can explain.
How we read both ranges on your Read
None of this makes the standard range meaningless. It is still the fastest way to catch a marker that is dangerously high or low, and it stays on every result we hand back. It is just not built to answer the question most women are actually asking, which is why a page of normal results and a body that does not feel normal can both be true at once.
On The Choosi Read, every one of the markers we run gets reported against both bands, standard and optimal, read next to your symptoms and history rather than flagged in isolation. For a handful of markers, thyroid and ferritin among them, Dr. Hall also weighs where the number tends to sit for women moving through perimenopause, since those values can shift in a predictable direction during that transition. That context adds to the optimal read. It does not replace it.
If your last set of labs came back normal but you still do not feel like yourself, the next step is reading those same numbers against an optimal band instead of stopping at the standard one.
Every marker on this page, standard range and optimal range both, is part of the full lab panel behind The Choosi Read.