Anemia is a condition in which you lack enough healthy red blood cells to carry adequate oxygen to your body’s tissues. Having anemia can make you feel tired and weak.
There are many forms of anemia, each with its own cause. Anemia can be temporary or long term, and it can range from mild to severe. See your doctor if you suspect that you have anemia. It can be a warning sign of serious illness.
Treatments for anemia range from taking supplements to undergoing medical procedures. You might be able to prevent some types of anemia by eating a healthy, varied diet.
- Aplastic anemia
- Iron deficiency anemia
- Sickle cell anemia
- Vitamin deficiency anemia
Anemia signs and symptoms vary depending on the cause. If the anemia is caused by a chronic disease, the disease can mask them, so that the anemia might be detected by tests for another condition.
Depending on the causes of your anemia, you might have no symptoms. Signs and symptoms, if they do occur, might include:
- Pale or yellowish skin
- Irregular heartbeats
- Shortness of breath
- Dizziness or lightheadedness
- Chest pain
- Cold hands and feet
At first, anemia can be so mild that you don’t notice it. But symptoms worsen as anemia worsens.
When to see a doctor
Make an appointment with your doctor if you’re feeling fatigued and you don’t know why.
Fatigue has many causes besides anemia, so don’t assume that if you’re tired you must be anemic. Some people learn that their hemoglobin is low, which indicates anemia, when they donate blood. If you’re told that you can’t donate because of low hemoglobin, make an appointment with your doctor.
Anemia occurs when your blood doesn’t have enough red blood cells.
This can happen if:
- Your body doesn’t make enough red blood cells
- Bleeding causes you to lose red blood cells more quickly than they can be replaced
- Your body destroys red blood cells
What red blood cells do
Your body makes three types of blood cells — white blood cells to fight infection, platelets to help your blood clot and red blood cells to carry oxygen throughout your body.
Red blood cells contain hemoglobin — an iron-rich protein that gives blood its red color. Hemoglobin enables red blood cells to carry oxygen from your lungs to all parts of your body and to carry carbon dioxide from other parts of the body to your lungs to be exhaled.
Most blood cells, including red blood cells, are produced regularly in your bone marrow — a spongy material found within the cavities of many of your large bones. To produce hemoglobin and red blood cells, your body needs iron, vitamin B-12, folate and other nutrients from the foods you eat.
Causes of anemia
Different types of anemia have different causes. They include:
- Iron deficiency anemia. This most common type of anemia is caused by a shortage of iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can’t produce enough hemoglobin for red blood cells.Without iron supplementation, this type of anemia occurs in many pregnant women. It is also caused by blood loss, such as from heavy menstrual bleeding, an ulcer, cancer and regular use of some over-the-counter pain relievers, especially aspirin, which can cause inflammation of the stomach lining resulting in blood loss.
- Vitamin deficiency anemia. Besides iron, your body needs folate and vitamin B-12 to produce enough healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production.Also, some people who consume enough B-12 aren’t able to absorb the vitamin. This can lead to vitamin deficiency anemia, also known as pernicious anemia.
- Anemia of inflammation. Certain diseases — such as cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, Crohn’s disease and other acute or chronic inflammatory diseases — can interfere with the production of red blood cells.
- Aplastic anemia. This rare, life-threatening anemia occurs when your body doesn’t produce enough red blood cells. Causes of aplastic anemia include infections, certain medicines, autoimmune diseases and exposure to toxic chemicals.
- Anemias associated with bone marrow disease. A variety of diseases, such as leukemia and myelofibrosis, can cause anemia by affecting blood production in your bone marrow. The effects of these types of cancer and cancer-like disorders vary from mild to life-threatening.
- Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases increase red blood cell destruction. You can inherit a hemolytic anemia, or you can develop it later in life.
- Sickle cell anemia. This inherited and sometimes serious condition is a hemolytic anemia. It’s caused by a defective form of hemoglobin that forces red blood cells to assume an abnormal crescent (sickle) shape. These irregular blood cells die prematurely, resulting in a chronic shortage of red blood cells.
These factors place you at increased risk of anemia:
- A diet lacking in certain vitamins and minerals. A diet consistently low in iron, vitamin B-12 and folate increases your risk of anemia.
- Intestinal disorders. Having an intestinal disorder that affects the absorption of nutrients in your small intestine — such as Crohn’s disease and celiac disease — puts you at risk of anemia.
- Menstruation. In general, women who haven’t had menopause have a greater risk of iron deficiency anemia than do men and postmenopausal women. Menstruation causes the loss of red blood cells.
- Pregnancy. If you’re pregnant and aren’t taking a multivitamin with folic acid and iron, you’re at an increased risk of anemia.
- Chronic conditions. If you have cancer, kidney failure, diabetes or another chronic condition, you could be at risk of anemia of chronic disease. These conditions can lead to a shortage of red blood cells.Slow, chronic blood loss from an ulcer or other source within your body can deplete your body’s store of iron, leading to iron deficiency anemia.
- Family history. If your family has a history of an inherited anemia, such as sickle cell anemia, you also might be at increased risk of the condition.
- Other factors. A history of certain infections, blood diseases and autoimmune disorders increases your risk of anemia. Alcoholism, exposure to toxic chemicals, and the use of some medications can affect red blood cell production and lead to anemia.
- Age. People over age 65 are at increased risk of anemia.
Left untreated, anemia can cause many health problems, such as:
- Severe fatigue. Severe anemia can make you so tired that you can’t complete everyday tasks.
- Pregnancy complications. Pregnant women with folate deficiency anemia may be more likely to have complications, such as premature birth.
- Heart problems. Anemia can lead to a rapid or irregular heartbeat (arrhythmia). When you’re anemic your heart must pump more blood to make up for the lack of oxygen in the blood. This can lead to an enlarged heart or heart failure.
- Death. Some inherited anemias, such as sickle cell anemia, can lead to life-threatening complications. Losing a lot of blood quickly results in acute, severe anemia and can be fatal.
Many types of anemia can’t be prevented. But you can avoid iron deficiency anemia and vitamin deficiency anemias by eating a diet that includes a variety of vitamins and minerals, including:
- Iron. Iron-rich foods include beef and other meats, beans, lentils, iron-fortified cereals, dark green leafy vegetables, and dried fruit.
- Folate. This nutrient, and its synthetic form folic acid, can be found in fruits and fruit juices, dark green leafy vegetables, green peas, kidney beans, peanuts, and enriched grain products, such as bread, cereal, pasta and rice.
- Vitamin B-12. Foods rich in vitamin B-12 include meat, dairy products, and fortified cereal and soy products.
- Vitamin C. Foods rich in vitamin C include citrus fruits and juices, peppers, broccoli, tomatoes, melons and strawberries. These also help increase iron absorption.
If you’re concerned about getting enough vitamins and minerals from food, ask your doctor whether a multivitamin might help.
Complete blood count (CBC)
A complete blood count (CBC) is a blood test used to evaluate your overall health and detect a wide range of disorders, including anemia, infection and leukemia.
A complete blood count test measures several components and features of your blood, including:
- Red blood cells, which carry oxygen
- White blood cells, which fight infection
- Hemoglobin, the oxygen-carrying protein in red blood cells
- Hematocrit, the proportion of red blood cells to the fluid component, or plasma, in your blood
- Platelets, which help with blood clotting
Abnormal increases or decreases in cell counts as revealed in a complete blood count may indicate that you have an underlying medical condition that calls for further evaluation.
Why it’s done
A complete blood count is a common blood test that’s done for a variety of reasons:
- To review your overall health. Your doctor may recommend a complete blood count as part of a routine medical examination to monitor your general health and to screen for a variety of disorders, such as anemia or leukemia.
- To diagnose a medical condition. Your doctor may suggest a complete blood count if you’re experiencing weakness, fatigue, fever, inflammation, bruising or bleeding. A complete blood count may help diagnose the cause of these signs and symptoms. If your doctor suspects you have an infection, the test can also help confirm that diagnosis.
- To monitor a medical condition. If you’ve been diagnosed with a blood disorder that affects blood cell counts, your doctor may use complete blood counts to monitor your condition.
- To monitor medical treatment. A complete blood count may be used to monitor your health if you’re taking medications that may affect blood cell counts.
How you prepare
If your blood sample is being tested only for a complete blood count, you can eat and drink normally before the test. If your blood sample will be used for additional tests, you may need to fast for a certain amount of time before the test. Your doctor will give you specific instructions.
What you can expect
For a complete blood count, a member of your health care team takes a sample of blood by inserting a needle into a vein in your arm, usually at the bend in your elbow. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.
The following are normal complete blood count results for adults:
|Red blood cell count||Male: 4.35-5.65 trillion cells/L*|
(4.35-5.65 million cells/mcL**)Female: 3.92-5.13 trillion cells/L
(3.92-5.13 million cells/mcL)
|Hemoglobin||Male: 13.2-16.6 grams/dL***|
(132-166 grams/L)Female: 11.6-15 grams/dL
|Hematocrit||Male: 38.3-48.6 percentFemale: 35.5-44.9 percent|
|White blood cell count||3.4-9.6 billion cells/L|
(3,400 to 9,600 cells/mcL)
|Platelet count||Male: 135-317 billion/L|
(135,000 to 317,000/mcL)Female: 157-371 billion/L
(157,000 to 371,000/mcL)
|* L = liter** mcL = microliter*** dL = deciliter|
Not a definitive test
A complete blood count is typically not a definitive diagnostic test. Depending on the reason your doctor recommended this test, results outside the normal range may or may not require follow-up. Your doctor may need to look at the results of a CBC along with results of other blood tests, or additional tests may be necessary.
For example, if you’re otherwise healthy and have no signs or symptoms of illness, results slightly outside the normal range on a complete blood count may not be a cause for concern, and follow-up may not be needed. Of if you’re undergoing cancer treatment, the results of a complete blood count outside the normal range may indicate a need to alter your treatment plan.
In some cases, if your results are significantly above or below the normal ranges, your doctor may refer you to a doctor who specializes in blood disorders (hematologist).
What the results may indicate
Results in the following areas above or below the normal ranges on a complete blood count may indicate a problem.
- Red blood cell count, hemoglobin and hematocrit. The results of your red blood cell count, hemoglobin and hematocrit are related because they each measure aspects of your red blood cells.If the measures in these three areas are lower than normal, you have anemia. Anemia causes fatigue and weakness. Anemia has many causes, including low levels of certain vitamins or iron, blood loss, or an underlying condition.A red blood cell count that’s higher than normal (erythrocytosis), or high hemoglobin or hematocrit levels, could point to an underlying medical condition, such as polycythemia vera or heart disease.
- White blood cell count. A low white blood cell count (leukopenia) may be caused by a medical condition, such as an autoimmune disorder that destroys white blood cells, bone marrow problems or cancer. Certain medications also can cause white blood cell counts to drop.If your white blood cell count is higher than normal, you may have an infection or inflammation. Or, it could indicate that you have an immune system disorder or a bone marrow disease. A high white blood cell count can also be a reaction to medication.
- Platelet count. A platelet count that’s lower than normal (thrombocytopenia) or higher than normal (thrombocytosis) is often a sign of an underlying medical condition, or it may be a side effect from medication. If your platelet count is outside the normal range, you’ll likely need additional tests to diagnose the cause.
For specifics about what your complete blood count results mean if they fall outside the normal ranges, talk to your doctor.
References: Mayo Clinic