Understanding Anemia: Simple Explanation for Patients
What is Anemia?
Anemia means you have fewer red blood cells than normal, or your red blood cells don't carry enough hemoglobin (the protein that carries oxygen throughout your body). 1 This results in less oxygen being delivered to your tissues and organs, which is why you may feel tired, weak, short of breath, or lightheaded. 2
Your body normally makes about 200 billion new red blood cells every day to replace old ones that wear out. 1 When something disrupts this balance—either by losing too many cells, destroying them too quickly, or not making enough new ones—anemia develops. 3, 4
How is Anemia Diagnosed?
Initial Blood Tests
The minimum workup includes a complete blood count (CBC) with specific measurements like mean corpuscular volume (MCV), red cell distribution width (RDW), reticulocyte count (young red blood cells), serum ferritin (iron stores), transferrin saturation (available iron), and C-reactive protein (CRP, which measures inflammation). 1
- Hemoglobin level tells us if you're anemic. For women, anemia is defined as hemoglobin below 12.0 g/dL; for men, below 13.0 g/dL. 1
- MCV tells us the size of your red blood cells—small (microcytic), normal (normocytic), or large (macrocytic). 1
- Reticulocyte count shows whether your bone marrow is responding appropriately by making new red blood cells. 1, 5
- Serum ferritin below 12 μg/dL confirms iron deficiency, though in patients with inflammation or chronic disease, ferritin can be falsely elevated up to 100 μg/dL and still indicate iron deficiency. 1
Additional Testing When Needed
More extensive workup may include vitamin B12, folic acid, haptoglobin, lactate dehydrogenase, and thyroid function tests, depending on your initial results. 1, 5 If your red blood cells are large (macrocytosis), vitamin B12 and folate levels are mandatory first-line tests. 6, 5
Common Types of Anemia
Iron Deficiency Anemia
This is the most common type, especially in women of childbearing age due to menstrual blood loss, and in men and postmenopausal women due to gastrointestinal bleeding. 1 Your red blood cells become small (microcytic) because there isn't enough iron to make hemoglobin properly. 1
Anemia of Chronic Disease
This occurs with long-term inflammatory conditions like inflammatory bowel disease, heart failure, or chronic kidney disease. 1 Your body has trouble using stored iron even though it's present, and inflammatory signals interfere with red blood cell production. 1
Vitamin Deficiency Anemia
Deficiency of vitamin B12 or folate causes large red blood cells (macrocytosis) because these vitamins are essential for proper red blood cell maturation. 6, 5 This is particularly important because B12 deficiency can cause irreversible nerve damage if not treated promptly. 6, 5
How is Anemia Managed?
Iron Deficiency Treatment
For iron deficiency anemia, oral iron supplementation is the first-line treatment for most patients. 1 However, if you have severe anemia, can't tolerate oral iron, or have inflammatory bowel disease, intravenous iron may be more effective. 1
Vitamin B12 Deficiency Treatment
If you have B12 deficiency with neurological symptoms (numbness, tingling, balance problems), you need hydroxocobalamin 1 mg intramuscularly on alternate days until symptoms stop improving, then 1 mg every 2 months for life. 6, 5 Without neurological symptoms, the treatment is 1 mg intramuscularly three times weekly for 2 weeks, then maintenance every 2-3 months for life. 6, 5
Folate Deficiency Treatment
Critical: Your doctor must always exclude vitamin B12 deficiency before treating folate deficiency, because giving folate alone when B12 is also low can mask the B12 deficiency and allow permanent nerve damage to occur. 6, 5 Once B12 deficiency is ruled out, folate deficiency is treated with oral folic acid 5 mg daily for at least 4 months. 6, 5
When Blood Transfusions Are Needed
Blood transfusions are reserved for severe situations: when hemoglobin drops below 7 g/dL, when you have symptoms of heart problems or severe weakness, or when other treatments haven't worked. 1 Transfusions provide immediate relief but don't fix the underlying problem, so you'll still need treatment for the cause of your anemia. 1
Important Follow-Up
Your doctor should monitor your blood counts regularly—at least every 3 months if you have chronic conditions like inflammatory bowel disease or chronic kidney disease. 1 Response to treatment should show hemoglobin improvement of at least 2 g/dL within 4 weeks. 5
If your anemia doesn't improve with appropriate treatment after 2-3 weeks, or if the cause remains unclear after initial testing, you need referral to a hematologist (blood specialist). 6, 7 This is especially important if you also have low white blood cells or platelets, which could indicate bone marrow problems. 5, 7
Common Pitfalls to Avoid
- Don't assume a single cause: You can have multiple types of anemia at once (for example, both iron deficiency and vitamin B12 deficiency), and all need to be treated. 7
- Inflammation masks iron deficiency: If you have an inflammatory condition, normal or even high ferritin levels don't rule out iron deficiency—your doctor needs to check transferrin saturation and RDW as well. 1, 5
- Medications matter: Certain drugs like methotrexate, azathioprine, and anticonvulsants can cause anemia or affect red blood cell size. 6, 5