Iron deficiency and anemia are commonly diagnosed and can result in significant negative health impacts if not treated. Intravenous iron offers a rapid treatment option that is often superior to oral iron. Learn more about your risks for iron deficiency and anemia with this quiz and use these helpful tools to interpret your hemoglobin and ferritin test results.
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For individuals suffering from iron deficiency anemia, the most common treatment is oral iron supplements. However, intravenous iron allows complete replacement of iron and alleviation of anemia in one (or more) sessions. With the development of safer solutions, IV iron has been used more often for anemic individuals with inflammatory bowel disease, gynecological and obstetric issues, renal failure, and cancer. Yet it’s still an underutilized method due to outdated methods and safety concerns. IV iron may be particularly helpful for older individuals, who may not even realize they have iron deficiency.
Anemia indicates that you don’t have enough healthy red blood cells to carry adequate oxygen to your body’s tissues. Iron deficiency is the most common cause of anemia worldwide, affecting approximately 27% of the world’s population. It’s more common in developing countries.
It’s important to note that iron deficiency can also occur without anemia, and is at least twice as common as anemia. Iron deficiency without anemia refers to low iron stores that don’t meet the body’s iron requirements. It has similar symptoms, diagnosis, and treatment options.
of the world's population is affected
by iron deficiency anemia
Iron deficiency causing anemia may be due to blood loss, menstruation and pregnancy in women and their children, malaria, hookworm, dietary conditions lacking adequate iron, celiac disease, cancer, kidney disease, and conditions causing an inability to absorb iron. For example, a 2023 study published in Nature reported that the rate for anemia was 40-45% in reproductive-age women in low- and middle-income countries. About 10% of individuals over 65 years of age and more than 20% of those over 85 are anemic. Anemia in the elderly is typically mild, but results in adverse outcomes like longer hospitalization, disability, increased mortality risk, and impacts on quality of life (fatigue, depression, frailty, etc.).
Iron deficiency is extremely common in individuals with chronic inflammation (chronic heart failure, chronic kidney disease, cancers, and inflammatory bowel diseases).
Initially, iron deficiency anemia can be so mild that it goes unnoticed. But as the body becomes more deficient in iron and anemia worsens, the signs and symptoms intensify. Note that iron deficiency without anemia has many of the same symptoms:
Anemia may be identified by the red blood cell count (hematocrit) or hemoglobin level in blood.
To understand if a person has iron deficiency, several different diagnostic tests are available.
Thus, a definitive diagnosis of iron deficiency with or without anemia usually considers serum ferritin, percent transferrin saturation (TSAT), and hemoglobin, which correlate best with iron status. You can ask for a ferritin test from your doctor, or order one from most laboratory testing services.
Want to know more? For a primer on the various measurements related to evaluation of iron deficiency, see Interpreting Iron Studies.
The definition of anemia varies according to age, sex, race, and how the blood was collected. An additional complexity is that medical guidelines for testing and interpreting data are not standardized and vary country by country.
The World Health Organization provides guidelines on interpreting hemoglobin levels for anemia. For example, anemia is diagnosed when hemoglobin is lower than a threshold for the following groups:
Ferritin levels under 50 raise the suspicion of iron deficiency, and levels under 30 mean it is likely. But for individuals with chronic inflammation, ferritin levels under 100 μg/L or TSAT levels below 20% signal iron deficiency.
A 2025 review on iron deficiency provides a useful interpretation of tests for adults:
Iron supplementation is usually the prescribed treatment for anemia. Iron can be taken via oral iron (tablets or liquid) and as an intravascular infusion. Oral iron frequently causes side effects (such as gastrointestinal problems, headache, cramps) leading to discontinuation and treatment failure in a significant portion of people.
Intravenous iron has many benefits over oral iron. A 2015 meta-analysis reported that oral iron supplement caused 2.6 times the odds of gastrointestinal side-effects compared to placebo or IV iron in participants who were not pregnant and did not have inflammatory bowel disease. Iron provided via IV also has the significant advantage of rapid replenishment of iron throughout the body. Often in as little as one or two transfusions, iron levels are completely recovered. In a randomized, controlled trial, hemoglobin reached a normal level in 80% of anemic women receiving 1-2 intravenous iron transfusions compared to 51% of women using oral iron.
IV iron is especially useful in people with IBD as it bypasses the gut where iron can actually make the symptoms of IBD worse. It is also useful to treat iron deficiency in women with heavy uterine bleeding, during pregnancy, bariatric surgery, restless legs syndrome, and high altitude sickness. For example, recent research shows that intravenous iron is a promising treatment for anemia in pregnant women (see our article on this topic).
Some doctors may be reluctant to use IV iron because an older high-molecular-weight iron called dextran was associated with severe infusion reactions. However, iron formulations used today are much safer.
Intravenous iron is currently underutilized, and should be considered especially in iron deficient individuals with chronic inflammatory conditions and when oral therapy is poorly tolerated or ineffective.
“It can take years to get low iron stores taken seriously — in my case, eight years. In 2014, I went to a top university hospital with a ferritin count of 10 — low by any standards. They basically ignored it. Eight years later, I got infusion treatment elsewhere and finally felt better.
All those years of trying to raise my ferritin count with pills and thinking infusions were still dangerous … Hopefully, you won’t have to learn the hard way like I did! If your ferritin is under 50 and you don’t feel right, and pills aren’t working, you deserve modern treatment.”
If you’ve been diagnosed with iron deficiency with or without anemia, talk to your doctor about treatment options to see if intravenous iron is right for you.
Learn more about your risks for iron deficiency and anemia with this educational quiz. To diagnose iron deficiency, evaluation of serum ferritin, hemoglobin, and transferrin saturation can be performed. If you already have blood test results, you can use these helpful tools to interpret your hemoglobin and ferritin levels.
If your doctor is not familiar with the modern use of intravenous iron to treat iron deficiency, the references under Additional Resources below may be useful. To find an iron infusion center, you can try this locator service from the National Infusion Center Association.
Learn more about your risks for iron deficiency and anemia with this educational quiz. To diagnose iron deficiency, evaluation of serum ferritin, hemoglobin, and transferrin saturation can be performed. If you already have blood test results, you can use these helpful tools to interpret your hemoglobin and ferritin levels.
See our searchable bibliography for a complete library of scientific publications on our projects.
Key publications on iron deficiency:
A: Although these conditions are related, they are not the same. Anemia occurs when you have a low number of red blood cells (or hemoglobin) that carry oxygen throughout your body. Iron deficiency is a low level of iron. Since iron is required to make red blood cells, it is a common cause of anemia.
A: Yes. You can have non-anemic iron deficiency, where your iron stores (ferritin) are low even though your hemoglobin is still in the “normal” range. Iron is used for more than just making red blood cells; it is essential for muscle function, brain health, and energy production in every cell. If your iron is low, you will feel the effects long before you technically become anemic.
A: Experts often suggest that a ferritin level below 30 ng/mL is a clear indicator of deficiency, while some people require levels above 50 or 100 ng/mL are required by people with certain risk factors, such as chronic inflammation, older age, or pregnancy.
A: Both anemia and low iron can cause symptoms like fatigue, cold hands, chest pain or shortness of breath, restless legs syndrome, headache or lightheadedness, pale skin, and others.
A: Anemia affects more than 27% of the world’s population. It is more common in the elderly as well as people who lack enough iron in their diet, and individuals with chronic inflammation.
A: The primary cause of iron deficiency for women is blood loss through menstruation. Pregnancy also significantly depletes iron stores because the body must produce extra blood for the fetus and placenta.
A: Oral iron is notorious for causing gastrointestinal issues like constipation, nausea, and stomach pain. Furthermore, when you take a high-dose iron pill, the hormone hepcidin increases and blocks the absorption of iron for the next 24–48 hours. This is why your doctor may recommend taking iron every other day, which may be more effective and easier on the stomach than taking it every day.
A: An infusion might be necessary if:
A: Many physicians were trained to only look at hemoglobin (the anemia test). The Parsemus Foundation is working to educate both the public and doctors on the importance of testing Ferritin and Iron Saturation (TSAT). You may need to specifically request a “Full Iron Panel” rather than just a “Complete Blood Count (CBC).”
A: Yes. While deficiency is more common, “iron overload” (Hemochromatosis) is a serious genetic condition where the body stores too much iron, which can damage the liver and heart. You should never start high-dose iron supplements without getting blood work done first to confirm you need it.
Last updated on October 28, 2026
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We occasionally share news about overlooked innovations in human and pet healthcare. Sign up to receive our human health and/or pet health e-newsletter.
We take your privacy seriously and will never share your contact information. See our Privacy Policy here.
The Parsemus Foundation is a private nonprofit operating foundation working to create meaningful improvements in human and pet health and welfare by advancing innovative and neglected medical research. Our aim is to educate medical professionals and the public about the latest developments in health and medicine.
You can email us at
info@parsemus.org
Our Professional Profile
can be found on ProPublica.
Write to Us
Parsemus Foundation,
2261 Market Street #24,
San Francisco, CA 94114
This website is educational and does not constitute medical advice or professional services. Those seeking personal medical advice should consult with a licensed physician.
