Iron levels: serum iron normal range, TIBC and iron saturation

Quick answer: for iron levels, MedlinePlus gives normal serum iron of 59 to 158 mcg/dL (10.6 to 28.3 micromol/L) for men and 37 to 145 mcg/dL (6.6 to 25.9 micromol/L) for women. Total iron-binding capacity (TIBC) is normally 171 to 505 mcg/dL for men and 149 to 492 mcg/dL for women, and iron saturation 20% to 50% for men and 15% to 45% for women. A single iron number means little alone; ferritin is the better guide to your stores.

Get the full iron panel at homeSerum iron, TIBC, UIBC, saturation and ferritin are on SiPhox Ultimate 360 and GLP Optimization.

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Iron levels normal range

All values from MedlinePlus; your lab's range may differ slightly. mcg/dL is the same as µg/dL. To convert serum iron from mcg/dL to micromol/L, multiply by 0.179.

What serum iron, TIBC and saturation measure

Iron moves around the body bound to a carrier protein called transferrin. The iron panel looks at that transport system from a few angles:

• Serum iron: how much iron is bound to transferrin in your blood right now.
• TIBC (total iron-binding capacity): how much iron your transferrin could carry if it were full. It tends to rise when the body is short of iron.
• UIBC (unsaturated iron-binding capacity): the spare capacity, TIBC minus serum iron.
• Iron saturation (transferrin saturation): serum iron divided by TIBC, as a percentage. Low saturation points toward too little iron; high saturation toward too much.
• Ferritin: the stored reserve. It is usually the first number a doctor looks at.

Worked example: a serum iron of 60 mcg/dL with a TIBC of 400 mcg/dL gives a saturation of 15% (60 divided by 400), at the bottom of the women's range and below the men's.

What low iron means

Low serum iron, especially with low saturation and low ferritin, points to iron deficiency. MedlinePlus lists these causes:

• Long-term bleeding in the digestive tract
• Heavy menstrual periods
• Intestinal conditions that reduce iron absorption
• Not enough iron in the diet
• Pregnancy

Serum iron can also be low with a normal or high ferritin when inflammation is locking iron away, which is why the panel has to be read as a whole. Iron deficiency in men and after menopause needs a cause found; the AGA guideline recommends gut evaluation in many of these cases. See your doctor rather than starting iron on your own.

Worked example: normal serum iron, low saturation

Say a 29-year-old vegetarian woman gets serum iron of 42 mcg/dL, TIBC of 450 mcg/dL and ferritin of 11 ng/mL. Her serum iron is inside the 37 to 145 mcg/dL women's range, so on its own it looks fine. The rest of the panel does not: saturation is 42 divided by 450, about 9%, well under the 15% lower limit for women; TIBC is near the top of its range, which fits a body short of iron; and a ferritin of 11 ng/mL is far below the 45 ng/mL cutoff the AGA uses for iron deficiency in people with anemia.

What might explain it: not enough iron in the diet and heavy periods are both on the MedlinePlus list of causes. The RDA for women 19 to 50 is 18 mg a day (NIH ODS).

Questions to take to her doctor:

• Do I have iron deficiency anemia, and should we check hemoglobin on a CBC?
• Should we look for blood loss, including heavy periods?
• Should I take iron, and should B12 be checked too, since I eat no meat?

What high iron means

MedlinePlus lists these causes of high serum iron:

• Hemochromatosis, an inherited condition that makes the body absorb too much iron
• Hemolytic anemia, where red blood cells break down too quickly
• Hepatitis or liver tissue damage (check ALT)
• Iron poisoning, and frequent blood transfusions

A persistently high saturation with high ferritin needs a doctor's review for iron overload. Iron supplements or multivitamins taken before the draw can also push the reading up, so mention them to whoever reads the result.

What moves iron levels

• Diet: the RDA is 8 mg of iron a day for men and 18 mg for women 19 to 50, and 8 mg for adults over 50 (NIH ODS).
• Blood loss: heavy periods, blood donation and bleeding in the gut lower iron over time.
• Medicines: MedlinePlus lists antibiotics, birth control pills, estrogens, blood pressure and cholesterol medicines, gout medicines, testosterone and deferoxamine as able to affect results. Do not stop any medicine before talking to your doctor.
• Supplements: iron pills raise serum iron and ferritin. Too much iron is harmful, so use them only on medical advice.

How to test iron

MedlinePlus says your provider will likely have you do the test in the morning or after fasting, so follow that when you can and keep it the same between tests. Serum iron is usually ordered as part of an iron panel (serum iron, TIBC and saturation) with ferritin, and often with a complete blood count to check hemoglobin. If you take an iron supplement, ask your doctor whether to skip it before the draw.

Which at-home tests include iron

Serum iron is on two SiPhox panels: Ultimate 360 and GLP Optimization. Both also include TIBC, UIBC, iron saturation and ferritin, which is the full iron panel.

Longevity Essentials and Thyroid Focus include ferritin but not serum iron, TIBC or saturation; Heart & Metabolic and Hormone Focus have no iron markers. SiPhox's EasyDraw instructions we read do not set a fasting rule, so collect at the same time of day each time. There is no included doctor review, so share abnormal results with your doctor. The GLP panel is covered on our GLP-1 blood test page, and the full service in our SiPhox review. Anemia can also come from low B12 or folate, both also on these two panels.

Ultimate 360

$249 + $25 shipping per test

62 biomarkers per test

Everything on the four core panels plus iron studies, B12 and folate, GGT and PSA.

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GLP Optimization

$199 + $25 shipping per test

46 biomarkers per test

Built for people on GLP-1 medication: metabolic, liver, kidney, nutrient and iron markers.

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Iron, ferritin, B12 and folate togetherUltimate 360 covers 62 biomarkers including the full iron panel, from one needle-free draw.

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