Iron test results: ferritin, serum iron, TIBC and transferrin saturation
Iron tests measure different things in the blood to check whether your body has too little or too much iron. Your provider reads them together with your symptoms, age, medical history and other blood tests such as the complete blood count. (MedlinePlus, iron tests)
What each test measures
You may have just one of these tests, or several together. (MedlinePlus, iron tests)
| Test | What it measures |
|---|---|
| Ferritin | A protein that stores iron. The blood level reflects how much iron is stored in your body. (MedlinePlus, ferritin) (MedlinePlus, ferritin ranges) |
| Serum iron | The amount of iron in the blood. It changes through the day and may be higher in the morning. (MedlinePlus, iron tests) (MedlinePlus, serum iron) |
| Transferrin and TIBC | Transferrin is the protein that carries iron in the blood. Total iron binding capacity (TIBC) shows how well iron can attach to it. (MedlinePlus, iron tests) (MedlinePlus, TIBC) |
| Transferrin saturation | How much of the transferrin is carrying iron, also called iron saturation (the ratio of iron to transferrin). (MedlinePlus, TIBC) (NIDDK, diagnosis) (NHS) |
The test is a blood sample from a vein in your arm. Your provider may ask you to fast for 12 hours, and the test is usually done in the morning. (MedlinePlus, ferritin)(MedlinePlus, iron tests) For TIBC, MedlinePlus says not to eat or drink for 8 hours. (MedlinePlus, TIBC) See fasting before a blood test.
Typical adult ranges
These are the common ranges MedlinePlus lists. Ranges vary slightly between labs, and some labs use different units or samples, so the range printed on your report is the one that applies to you. (MedlinePlus, ferritin ranges)(MedlinePlus, serum iron)(MedlinePlus, TIBC)
| Test | Men | Women |
|---|---|---|
| Ferritin | 30 to 400 ng/mL | 13 to 150 ng/mL |
| Serum iron | 59 to 158 mcg/dL (10.6 to 28.3 micromol/L) | 37 to 145 mcg/dL (6.6 to 25.9 micromol/L) |
| TIBC | 171 to 505 mcg/dL (30.6 to 90.3 micromol/L) | 149 to 492 mcg/dL (26.7 to 88.0 micromol/L) |
| Iron (transferrin) saturation | 20% to 50% | 15% to 45% |
Source for the ranges: the MedlinePlus ferritin, serum iron and TIBC pages. (MedlinePlus, ferritin ranges)(MedlinePlus, serum iron)(MedlinePlus, TIBC) The lower the ferritin, even within the normal range, the more likely it is that iron stores are low. (MedlinePlus, ferritin ranges) Some medicines can change iron results, and iron levels may be lower for women during their periods. (MedlinePlus, iron tests)
What low results can mean
- Low ferritin: anemia caused by low iron, which may come from heavy periods, bleeding in the gut, bleeding from an injury, poor absorption of iron or too little iron in the diet. (MedlinePlus, ferritin ranges)
- Low serum iron: long-term bleeding in the digestive tract, heavy periods, poor absorption, too little iron in the diet, or pregnancy. (MedlinePlus, serum iron)
- High TIBC: usually means iron supplies are low, as in iron deficiency anemia or late pregnancy. (MedlinePlus, TIBC)
- Other causes of low iron results: another type of anemia, or thalassemia, an inherited blood disorder. Not everyone with low iron has anemia. (MedlinePlus, iron tests) See complete blood count results for hemoglobin and red cell size.
What high results can mean
- High ferritin: too much iron in the body, but also inflammation (for example from an infection or surgery), an autoimmune disorder, liver disease, cancer, obesity, alcohol use disorder or an overactive thyroid. (MedlinePlus, ferritin) The ACG notes that among people with high ferritin who do not have the main hemochromatosis gene pattern, fatty liver disease and alcohol-related liver disease are more common than hemochromatosis. (ACG, 2019)
- High serum iron: hemochromatosis, red cells being destroyed too quickly (hemolytic anemia), hepatitis or other liver damage, iron poisoning, or frequent blood transfusions. (MedlinePlus, serum iron)
- Low TIBC: can come with inflammation, liver disease, low blood protein, malnutrition, hemolytic or sickle cell anemia, or pernicious anemia. (MedlinePlus, TIBC)
- High transferrin saturation: a high ratio of iron to transferrin may suggest hemochromatosis, and a high ferritin is also typical of it. (NIDDK, diagnosis)
A result outside the range does not always mean you have a condition that needs treatment. (MedlinePlus, ferritin)(MedlinePlus, iron tests)
Iron tests in pregnancy
For pregnant adolescents and adults without symptoms, the USPSTF found the evidence insufficient to weigh the benefits and harms of screening for iron deficiency and iron deficiency anemia (I statement, 2024). It stresses that this is neither a recommendation for nor against screening, but a call for more research. It also notes there is no agreed ferritin level that defines iron deficiency. (USPSTF, 2024) The statement does not apply to pregnant people with symptoms of iron deficiency or certain blood conditions. (USPSTF, 2024)
Testing for hereditary hemochromatosis
Hereditary hemochromatosis makes the body absorb too much iron from food, and over time the iron can build up and damage the liver, heart, pancreas, glands and joints. (NIDDK) It often causes no symptoms for years, and symptoms usually begin after age 40, about 10 years later in women than in men on average. (NIDDK, symptoms)
- Who is tested: the NHS suggests speaking to a GP about testing if you have persistent symptoms, or if a parent or sibling has been diagnosed, even if you have no symptoms. (NHS)
- The steps: blood tests for transferrin saturation and ferritin come first. If they suggest hemochromatosis, a gene test follows; finding two copies of the HFE gene with the C282Y change confirms primary (inherited) hemochromatosis. (NHS)(NIDDK, diagnosis)
- Ferritin and the liver: the ACG uses a ferritin below 1,000 ng/mL at diagnosis to identify people at low risk of advanced liver scarring. (ACG, 2019)
- Population screening: the USPSTF has made its hemochromatosis screening topic inactive, so it has no current recommendation on it. (USPSTF, inactive topic)
Where they differ:
- Screening in pregnancy: the USPSTF found too little evidence to recommend for or against it, (USPSTF, 2024) while the USPSTF reports that ACOG, the AAFP and the CDC recommend screening all pregnant people for anemia at the first prenatal visit, and ACOG again at 24 to 28 weeks. (USPSTF, 2024)
- What defines low iron: studies reviewed by the USPSTF defined iron deficiency as a ferritin below 12 or 20 micrograms per liter (the same as ng/mL), and the USPSTF says there is no consensus on the exact level, (USPSTF, 2024) while MedlinePlus lists a lower limit of 13 ng/mL for women and 30 ng/mL for men. (MedlinePlus, ferritin ranges)
Your doctor decides what your result means for you.
This page does not give supplement, diet, medicine or treatment advice. If you have a flagged result, see after an abnormal screening result for questions to ask.
Questions people ask
What is a normal ferritin level?
MedlinePlus gives 30 to 400 ng/mL for men and 13 to 150 ng/mL for women, but ranges vary between labs. The lower the ferritin, even within the normal range, the more likely it is that iron stores are low. Use the range printed on your own report. (MedlinePlus, ferritin ranges)
Can ferritin be high without too much iron?
Yes. Inflammation from an infection or surgery, autoimmune disease, liver disease, cancer, obesity, alcohol use disorder and an overactive thyroid can all raise ferritin. The ACG notes that fatty liver disease and alcohol-related liver disease are more common causes than hemochromatosis in many people with high ferritin. (MedlinePlus, ferritin) (ACG, 2019)
Do I need to fast for an iron test?
Your provider may ask you to fast for 12 hours and to have the test in the morning, because blood iron changes through the day and after taking iron. (MedlinePlus, iron tests) (MedlinePlus, ferritin) (MedlinePlus, serum iron)
Should pregnant people be screened for low iron?
The USPSTF found the evidence insufficient to weigh the benefits and harms of screening pregnant people without symptoms for iron deficiency (I statement, 2024). It says this is a call for more research, not a recommendation for or against screening. (USPSTF, 2024)
Who should be tested for hemochromatosis?
The NHS suggests speaking to a GP about testing if you have persistent symptoms or a parent or sibling has been diagnosed. Doctors usually start with blood tests for transferrin saturation and ferritin, then a gene test if those suggest it. (NHS) (NIDDK, diagnosis)