← Blood tests
Soluble Transferrin Receptor (sTfR)
Specialistalso —
What it isA fragment of the transferrin receptor that iron-hungry cells release into blood. The hungrier the body's tissues are for iron, the more sTfR appears.
DoesReports cellular iron demand independent of inflammation.
GoodMid-range sTfR signals balanced iron supply and demand.
BadHigh sTfR confirms iron deficiency even when ferritin is elevated by inflammation — the cleanest tool to disentangle these.
- Standard
- 2.2–5.0 mg/L.
- Optimal
- 2.5–4.5 mg/L (narrow target)
- Modifiers
- Not significantly affected by inflammation.
How to optimize
- Lifestyle
- —
- Diet
- Iron-rich foods if deficient.
- Supplements
- Iron bisglycinate if true deficiency confirmed.
- Peptides
- —
- Drugs
- IV iron for severe deficiency. --
Reference ranges are general adult lab norms; optimal ranges are editorial picks from the longevity literature — not medical advice. Always interpret results with your physician.
within Iron