To diagnose iron deficiency anemia, your doctor may run tests to look for:
- Red blood cell size and color. With iron deficiency anemia, red blood cells are smaller and paler in color than normal.
- Hematocrit. This is the percentage of your blood volume made up by red blood cells. Normal levels are generally between 35.5 and 44.9 percent for adult women and 38.3 to 48.6 percent for adult men. These values may change depending on your age.
- Hemoglobin. Lower than normal hemoglobin levels indicate anemia. The normal hemoglobin range is generally defined as 13.2 to 16.6 grams (g) of hemoglobin per deciliter (dL) of blood for men and 11.6 to 15 g/dL for women.
- Ferritin. This protein helps store iron in your body, and a low level of ferritin usually indicates a low level of stored iron.
Additional diagnostic tests
If your bloodwork indicates iron deficiency anemia, your doctor may order additional tests to identify an underlying cause, such as:
- Endoscopy. Doctors often check for bleeding from a hiatal hernia, an ulcer or the stomach with the aid of endoscopy. In this procedure, a thin, lighted tube equipped with a video camera is passed down your throat to your stomach. This allows your doctor to view the tube that runs from your mouth to your stomach (esophagus) and your stomach to look for sources of bleeding.
- Colonoscopy. To rule out lower intestinal sources of bleeding, your doctor may recommend a procedure called a colonoscopy. A thin, flexible tube equipped with a video camera is inserted into the rectum and guided to your colon. You're usually sedated during this test. A colonoscopy allows your doctor to view inside some or all of your colon and rectum to look for internal bleeding.
- Ultrasound. Women may also have a pelvic ultrasound to look for the cause of excess menstrual bleeding, such as uterine fibroids.
Your doctor may order these or other tests after a trial period of treatment with iron supplementation.
- Ferritin test
- Hematocrit test
- Hemoglobin test
- Upper endoscopy
To treat iron deficiency anemia, your doctor may recommend that you take iron supplements. Your doctor will also treat the underlying cause of your iron deficiency, if necessary.
Your doctor may recommend over-the-counter iron tablets to replenish the iron stores in your body. Your doctor will let you know the correct dose for you. Iron is also available in liquid form for infants and children. To improve the chances that your body will absorb the iron in the tablets, you may be instructed to:
- Take iron tablets on an empty stomach. If possible, take your iron tablets when your stomach is empty. However, because iron tablets can upset your stomach, you may need to take your iron tablets with meals.
- Don't take iron with antacids. Medications that immediately relieve heartburn symptoms can interfere with the absorption of iron. Take iron two hours before or four hours after you take antacids.
- Take iron tablets with vitamin C. Vitamin C improves the absorption of iron. Your doctor might recommend taking your iron tablets with a glass of orange juice or with a vitamin C supplement.
Iron supplements can cause constipation, so your doctor may also recommend a stool softener. Iron may turn your stools black, which is a harmless side effect.
Iron deficiency can't be corrected overnight. You may need to take iron supplements for several months or longer to replenish your iron reserves. Generally, you'll start to feel better after a week or so of treatment. Ask your doctor when to have your blood rechecked to measure your iron levels. To be sure that your iron reserves are replenished, you may need to take iron supplements for a year or more.
Treating underlying causes of iron deficiency
If iron supplements don't increase your blood-iron levels, it's likely the anemia is due to a source of bleeding or an iron-absorption problem that your doctor will need to investigate and treat. Depending on the cause, iron deficiency anemia treatment may involve:
- Medications, such as oral contraceptives to lighten heavy menstrual flow
- Antibiotics and other medications to treat peptic ulcers
- Surgery to remove a bleeding polyp, a tumor or a fibroid
If iron deficiency anemia is severe, you may need iron given intravenously or you may need blood transfusions to help replace iron and hemoglobin quickly.
Request an Appointment at Mayo Clinic
From Mayo Clinic to your inbox
Sign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health.
To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.
Preparing for your appointment
Make an appointment with your doctor if you have any signs and symptoms that worry you. If you're diagnosed with iron deficiency anemia, you may need tests to look for a source of blood loss, including tests to examine your gastrointestinal tract.
Here's some information to help you get ready for your appointment, and what to expect from your doctor.
What you can do
- Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications, vitamins or supplements you're taking.
- Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. For iron deficiency anemia, some basic questions to ask your doctor include:
- What's the most likely cause of my symptoms?
- Are there other possible causes for my symptoms?
- Is my condition likely temporary or long lasting?
- What treatment do you recommend?
- Are there any alternatives to the primary approach that you're suggesting?
- I have another health condition. How can I best manage these conditions together?
- Are there any dietary restrictions that I need to follow?
- Are there any brochures or other printed material that I can take with me? What websites do you recommend?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to spend more time on. Your doctor may ask:
- When did you begin experiencing symptoms?
- How severe are your symptoms?
- Does anything seem to improve your symptoms?
- What, if anything, appears to worsen your symptoms?
- Have you noticed unusual bleeding, such as heavy periods, bleeding from hemorrhoids or nosebleeds?
- Are you a vegetarian?
- Have you recently donated blood more than once?
By Mayo Clinic Staff
Jan. 04, 2022