Serum Iron
Serum iron reflects circulating iron bound to transferrin at the time of sampling. Population values vary by sex and age, but the distribution is also shaped by diurnal variation and recent iron intake.
Unit: µg/dL · 12 slices · age and sex · 1 source
Filed under panels: Iron Studies · topics: Hematology
These pages use serum iron from the NHANES iron-status dataset. Serum iron measures the amount of iron circulating in blood bound to transferrin. Because it shifts with time of day, inflammation, supplementation, and recent intake, it is typically interpreted together with ferritin, TIBC, and transferrin saturation rather than in isolation.
Population Distribution
Browse by Demographic
| Age (years) | male (µg/dL) | female (µg/dL) |
|---|---|---|
| 20-29 | 50–177 (89) | 28–163 (72) |
| 30-39 | 47–157 (89) | 27–145 (75) |
| 40-49 | 52–169 (94) | 29–147 (77) |
| 50-59 | 48–155 (90) | 37–140 (80) |
| 60-69 | 41–147 (89) | 46–134 (83) |
| 70+ | 44–149 (86) | 41–126 (79) |
Frequently Asked Questions
Why is serum iron more variable than ferritin?
Serum iron changes over short time scales with diurnal rhythms, inflammation, recent intake, and iron supplementation. Ferritin is usually more stable because it reflects stored iron rather than momentary circulating iron.
Should serum iron be interpreted alone?
Usually no. Serum iron is most informative when interpreted alongside ferritin, TIBC, and transferrin saturation, which together describe iron stores and transport capacity.
How do I convert µg/dL to µmol/L?
Multiply by 0.179. For example, 100 µg/dL is approximately 17.9 µmol/L.