Iron Studies — Serum Iron, TIBC and Transferrin Saturation
Iron studies are a group, not a single test: serum iron, TIBC and transferrin saturation together separate iron deficiency from iron overload in a way that no single marker can.
Iron studies are a group, not a single test: serum iron, TIBC and transferrin saturation together separate iron deficiency from iron overload in a way no single marker can.
The biomarker
- Name: Iron Studies (serum iron, TIBC, transferrin saturation)
- Units: mcg/dL (serum iron, TIBC); % (transferrin saturation)
- Standard range:
- Serum iron: 59–158 mcg/dL (male) / 37–145 mcg/dL (female)
- TIBC: 171–505 mcg/dL (male) / 149–492 mcg/dL (female)
- Transferrin saturation: 20–50% (male) / 15–45% (female) — varies between laboratories
- Optimal range: no separate longevity "optimal" band is published — both deficiency and overload carry harm, so mid-range is the sensible target
How to read your result
| Pattern | What it may indicate |
|---|---|
| Low saturation (low iron + high TIBC + low ferritin) | Classic iron-deficiency pattern |
| High saturation (raised saturation + raised ferritin) | Raises the question of iron overload (haemochromatosis) — followed up clinically |
| Ferritin caveat | Ferritin is an acute-phase protein that rises with inflammation, which can mask a deficiency — read it alongside hs-CRP |
| Daily variation | Serum iron swings substantially through the day and with recent intake, which is why the panel is drawn fasting |
| Interpret with CBC | Read alongside haemoglobin and red-cell indices from the full blood count |
What moves the needle
- Never supplement on a hunch: excess iron is not excreted, and supplementing without a confirmed deficiency causes harm.
- Preparation: do not eat or drink for 8 hours before the test.
- Supplements: pause iron supplements before the draw as your clinician directs, and list them regardless — they distort serum iron sharply.
- If deficient: identify the cause before treating — unexplained iron deficiency in an adult is investigated, not simply supplemented.
- If overloaded: a raised saturation with raised ferritin goes to a clinician — iron overload damages the liver, heart and pancreas.
Why this test is worth asking for
- Serum iron alone cannot separate deficiency from overload — transferrin saturation, calculated from serum iron divided by TIBC, is what makes the distinction.
- Ferritin can appear normal or elevated during inflammation even when iron stores are genuinely depleted; reading it alongside serum iron and TIBC corrects for this.
- The "never supplement on a hunch" action is the reason the test matters: the direction of treatment (replenish or restrict) depends entirely on which pattern the panel shows.
Related protocols
- Ferritin — Iron Storage
- CMP — The 14 Numbers on Your Annual Panel
- CBC — What the Full Blood Count Shows
Sources
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
