FM-calibrated ranges: why 'in range' isn't the same as 'in target'

Open a LabCorp panel and every analyte comes with a reference range printed next to it. TSH 0.4 to 4.5. Vitamin D, 25-OH, greater than 20. Free T3, 2.0 to 4.4. Ferritin, 15 to 300.

Those ranges are useful, but they answer a specific question: where does this value sit relative to the population the lab used to define normal. The population is large and statistically defined, and it’s often a population that walked into a lab because something was already wrong.

FM clinicians are usually asking a different question.

What the two ranges are actually for

The lab-default range is a screening tool. Its job is to flag values that are unambiguously outside the distribution of the reference population. A TSH of 8.5 gets flagged. A TSH of 4.2 doesn’t, because 4.2 is inside the lab’s printed range, even though the patient feels cold and tired and has been gaining weight.

The FM target range is a clinical-management tool. Its job is to define where a patient should sit to feel and function well. It’s narrower, and it’s been refined over years of FM physicians watching what actually correlates with patient outcomes.

Neither range is wrong. They’re answering different questions.

A handful of worked examples

A few of the analytes where the two ranges diverge most:

• TSH. Lab-default: 0.4 to 4.5 mIU/L. FM target: 0.5 to 2.0. A TSH of 4.2 is “in range” by the lab’s print but well above where most FM physicians want their thyroid-treated patients to sit.
• Vitamin D, 25-OH. Lab-default: greater than 20 ng/mL. FM target: 50 to 80. A patient at 28 is “sufficient” by lab default and undertreated by FM target.
• Free T3. Lab-default: 2.0 to 4.4 pg/mL. FM target: 3.2 to 4.2. A Free T3 at 2.4 is “normal” by the lab and at the bottom of the FM working window.
• Ferritin (women). Lab-default: 15 to 300 ng/mL. FM target: 70 to 150. A ferritin of 22 is “in range” by lab default and well below where most FM physicians want it for energy, hair, and exercise tolerance.

There are more. Fasting insulin, hs-CRP, magnesium RBC, homocysteine, the full thyroid panel beyond TSH. The pattern is consistent: the lab-default range is wide enough to miss most of what an FM physician is treating.

How Helose handles this

Every row in a Helose-assembled lab panel carries two range badges. One is the lab-default range, exactly as the lab printed it. The other is the FM target range, drawn from the clinic’s own configured profile.

By default, the briefing shows the FM target. So a TSH of 4.2 shows up as “above target” with the FM range visible, and the lab-default range is one click away if the physician wants to see it. The doctor never loses access to the original lab reference; it’s just not the primary frame.

A few specifics about how this works in practice.

The clinic’s target ranges are configurable. Different FM practices have different preferences. A Hashimoto’s-focused clinic and a metabolic-focused clinic might pick slightly different TSH targets, and both should be able to set their own without filing a ticket.

The badge is stateless. Helose doesn’t say “this is concerning” or “this needs follow-up.” It says “above target” or “below target” or “within target” with the two ranges visible. The interpretation of what to do about it is the physician’s.

The lab source is always shown. A Free T3 from a Genova panel and a Free T3 from LabCorp are on different assays, and a careful FM physician will want to know which assay produced the number before they compare it to a value from six months ago. The badge doesn’t paper over the assay difference; it just adds the second frame of reference.

The target range applies to the briefing summary view and the full portfolio view. It’s not a chart-wide toggle; it’s a persistent annotation on every analyte that has an FM target configured.

Why this isn’t a complaint about labs

Lab reference ranges are doing the job they were built for. They’re a population-level screening tool, and they’re calibrated for a population-level question. The decision to use them as a clinical-management tool is a clinician’s, and FM physicians made that decision a long time ago when they decided the lab’s frame wasn’t the right one for their patients.

What Helose does is small. It carries both frames in the chart so the FM physician doesn’t have to mentally re-anchor every value to a different range. The briefing reads the way an FM physician already reads a panel, with the clinically meaningful target visible by default and the population-level range available when it’s useful.

This isn’t about saying labs are wrong. It’s about meeting FM physicians where they actually work.