Transferrin Blood Test: Low, Normal or High?

Type the transferrin from your iron panel. You see it against the adult ranges Mayo Clinic Laboratories, Labcorp and Cedars-Sinai print, the TIBC Mayo calculates from it, and — if you add the serum iron from the same report — your transferrin saturation by Mayo’s formula. Ferritin, your lab’s own range and your doctor have the last word.

250 mg/dL is

Inside all three printed ranges 250 mg/dL = 2.50 g/L

250 mg/dL: inside Mayo Clinic Laboratories’ 200–360 mg/dL for adults, inside Labcorp’s 192–364 mg/dL for women 18 to 80, inside Cedars-Sinai’s 215–380 mg/dL.

TIBC 295 mcg/dL (52.8 µmol/L) by Mayo Clinic Laboratories’ “Total iron-binding capacity (TIBC) = Transferrin x 1.18”: inside the 149–492 mcg/dL MedlinePlus prints for women, and inside Mayo’s 250–400 mcg/dL.

Labcorp: “Transferrin is responsible for 50% to 70% of the iron binding capacity of serum. Since other proteins may bind iron, transferrin is not the same as TIBC.” If your report prints its own TIBC, that measured line is the one to read — the TIBC Level Checker places it.

That is inside all three printed ranges. The range on your own lab report — and your ferritin — are what your doctor reads it against.

Mayo Clinic Laboratories: “However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.” Check a ferritin result.

What moves it, in the sources’ words

Cedars-Sinai: “Test results may vary depending on your age, sex, and health history. Your test results may also vary depending on the lab used.”
Mayo Clinic Laboratories: “The circulating concentration increases in response to iron deficiency and decreases in response to iron overload.”

The adult transferrin ranges the sources print (mg/dL)
Source	Women	Men
Mayo Clinic Laboratories, adults	200–360	200–360
Labcorp, 18 to 80	192–364	177–329
Labcorp, over 80	149–313	149–313
Cedars-Sinai	215–380	215–380

This is not medical advice and it does not diagnose anything. It shows where a number sits against published ranges; what your result means for you depends on your lab, your ferritin, your other results, your history and your doctor.

Transferrin ranges run from 200 to 360 mg/dL for adults at one lab to 215 to 380 mg/dL at another, and one splits by sex: 192 to 364 mg/dL for women and 177 to 329 mg/dL for men aged 18 to 80. A result near an edge can be inside one range and outside another. It rises when iron runs low and falls with iron overload.

How to use it

Type the transferrin line from your iron panel, say whether it is printed in mg/dL or g/L, and pick the ranges for women or men and your age band. It shows where your result sits against each adult range, the three side by side, and what moves it. Below that is the TIBC calculated from your transferrin (Transferrin x 1.18), placed against the TIBC ranges. If the same report prints a serum iron, type it too and you’ll get your transferrin saturation. It does not diagnose anything.

What transferrin is

Transferrin is the main protein that moves iron through your blood, binding it strongly at your body’s normal pH. Your liver makes it, and when your body’s stores of iron run low, your liver makes more to get more iron into your blood. The amount in your blood also depends on liver function and nutritional status, and it’s generally only 25% to 30% saturated with iron.

The adult ranges

Adult transferrin ranges in mg/dL (g/L is ÷ 100)
Source	Women	Men
Mayo Clinic Laboratories, adults	200–360 mg/dL (2.00–3.60 g/L)	200–360 mg/dL (2.00–3.60 g/L)
Labcorp, 18 to 80	192–364 mg/dL (1.92–3.64 g/L)	177–329 mg/dL (1.77–3.29 g/L)
Labcorp, over 80	149–313 mg/dL (1.49–3.13 g/L)	149–313 mg/dL (1.49–3.13 g/L)
Cedars-Sinai	215–380 mg/dL (2.15–3.80 g/L)	215–380 mg/dL (2.15–3.80 g/L)

Test results may vary depending on your age, sex, health history and the lab used. All three ranges are in mg/dL, and the g/L figures are the same amounts divided by 100. Over age 80, one lab lists 149 to 313 mg/dL. This checker is for adults.

Transferrin and TIBC: the same carrier, two numbers

You can estimate TIBC from a transferrin: Transferrin x 1.18, so a transferrin of 250 mg/dL gives a TIBC of 295 mcg/dL. But transferrin is responsible for only 50% to 70% of the iron binding capacity of serum, and other proteins may bind iron too, so transferrin is not the same as TIBC. If your report prints a TIBC its lab measured, read that one. The TIBC Level Checker places it.

With a serum iron, the saturation is (Iron / TIBC) x 100, and the degree of saturation is a more useful indicator of functional iron depletion or overload than transferrin alone.

What raises or lowers it

Transferrin rises in response to iron deficiency, in pregnancy and with oral contraceptives, though it may not rise in iron-deficient states with severe protein malnutrition (for example, kwashiorkor).

It falls with iron overload, malnutrition, inflammation, liver disease and nephrotic syndrome, and in chronic inflammatory states, hereditary atransferrinemia, some acquired liver disease, neoplasia and renal disease. It drops when inflammation is present, even though it varies only about 5% within a person.

Many other health conditions can cause high or low levels, and aspirin, antibiotics and birth control pills can affect your results.

Ferritin comes first

If your question is “is my iron low?”, serum ferritin is a much more sensitive and reliable test for iron deficiency. Read transferrin beside a ferritin result, not instead of one. The Ferritin Level Checker places it against the NIH’s and the WHO’s lines.

Before the blood draw

You may need to fast for a period of time, so check with your doctor for specific instructions. Transferrin drives the daily swing in serum iron, which peaks in the morning, so the serum iron beside it depends on the hour, even though transferrin itself varies only about 5% from day to day. Ask the person who ordered the test before changing anything you take.

Worked examples

250 mg/dL, woman, 18 to 80: inside all three ranges. TIBC by the formula: 295 mcg/dL, inside both TIBC ranges.
190 mg/dL, man, 18 to 80: inside 177–329, under 200 and under 215, so inside 1 of the 3.
400 mg/dL, woman: above all three. With a serum iron of 40 mcg/dL, the TIBC is 472 mcg/dL and the saturation 40 ÷ 472 × 100 = 8.5%: under both saturation ranges.
2.5 g/L, woman (a lab outside the US): 250 mg/dL, inside all three. With a serum iron of 15 µmol/L, the saturation is 28.4%.

Common mistakes

Reading transferrin as an iron level. It is the carrier, not the cargo, and a high transferrin goes with low iron supplies.
Confusing transferrin with transferrin saturation. Saturation is a percent; transferrin is in mg/dL or g/L. The Iron Saturation Checker places a printed saturation.
Mixing up mg/dL and g/L. 2.5 g/L is 250 mg/dL; the checker flags a number that only makes sense in the other unit.
Treating a calculated TIBC as a measured one. Transferrin is not the same as TIBC, so a TIBC your lab printed outranks the one worked out here.
Skipping the ferritin. Ferritin is the more sensitive and reliable test for iron deficiency.

Frequently asked questions

What is a transferrin blood test?

It measures the amount of the iron transport protein transferrin in your blood, the protein that moves iron throughout the body.

What is a normal transferrin level?

Ranges vary by lab: 200 to 360 mg/dL for adults, 192 to 364 mg/dL for women and 177 to 329 mg/dL for men aged 18 to 80 (149 to 313 over 80), or 215 to 380 mg/dL. Your lab’s printed range is the one your doctor uses.

What does high transferrin mean?

It goes up in response to iron deficiency, and also in pregnancy and with oral contraceptives. Ferritin is the test that settles the iron question, with your doctor.

What does low transferrin mean?

A low transferrin can come from malnutrition, inflammation, liver disease or nephrotic syndrome, and it also falls with iron overload. Many other health conditions can cause high or low levels.

How do you calculate TIBC from transferrin?

Multiply by 1.18. A transferrin of 300 mg/dL gives 354 mcg/dL. Other labs measure the TIBC directly, and the two are not the same number.

Transferrin vs ferritin: what is the difference?

Transferrin carries iron through the blood, and ferritin stores it. Ferritin holds most of your body’s iron reserves and is a much more sensitive and reliable test for iron deficiency.

Is transferrin the same as transferrin saturation?

No. Transferrin is how much of the carrier protein is in your blood, and saturation is the percent of its iron seats that are filled.

The whole panel at once — every line on one screen, and whether iron + UIBC = TIBC and the saturation add up: the Iron Panel Reader. More iron and blood-count checkers: the TIBC Level Checker, the UIBC Level Checker, the Iron Saturation Checker, the Serum Iron Level Checker, the Ferritin Level Checker and the Hemoglobin Level Checker.

Transferrin Level Checker