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NUTRIENTS & INFLAMMATION
Also printed as: Iron · Fe · Serum Fe
Educational only — not medical advice.
Serum iron measures the iron currently travelling in your bloodstream bound to transferrin. It is not a measure of your iron stores — that is ferritin. It fluctuates a great deal with time of day and with recent meals or supplements.
Serum iron on its own is one of the least reliable iron markers. It becomes useful when combined with TIBC to calculate transferrin saturation, which is the number clinicians actually use.
TYPICAL ADULT RANGE
Many labs report roughly 60–170 µg/dL for adults. Ranges vary by lab, and levels swing considerably through the day. Reported in µg/dL.
Reference ranges vary by lab, by method, and by age and sex. Always read your own result against the range printed on your report.
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A low serum iron can reflect genuinely low stores, but it just as often reflects timing — levels are lower later in the day and dip with recent inflammation or infection. Because of that swing, a low serum iron alone is not enough to conclude anything. Your doctor will read it with ferritin and transferrin saturation, which together give a much steadier answer.
A high serum iron very commonly follows an iron supplement or a multivitamin taken in the day or two before the draw — this is the most frequent explanation by far, and it is why labs often ask you to hold supplements beforehand. Morning draws read higher than afternoon ones. Alcohol, liver conditions, and genuine iron overload are the other possibilities, which is why a persistently high value alongside a high transferrin saturation is a routine reason for your doctor to look further.
Your doctor is the one who can read this number against your history, symptoms, and medications.
Educational only — not medical advice. Lab results only mean something alongside your history, symptoms, medications, and the rest of your panel. Bring questions to your doctor; they are the one who can interpret your results for you.
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