What Does It Mean When Your Red Blood Cells Are Low?

A low red blood cell count means you have anemia, a condition that could be caused by a variety of factors like blood loss, genetic disorders, cancer treatments and other causes. Discovering anemia is often the starting point to diagnosing an underlying condition.

Red blood cells carry oxygen in the blood. When a person has low red blood cells (anemia), the body may not be getting the oxygen it needs.

What Are Symptoms of Low Red Blood Cells (Anemia)?

Many people with low red blood cells (anemia) have no symptoms. When symptoms occur, they may include: 

• Irritability 
• Fatigue 
• Weakness
• Headache
• Difficulty exercising (due to shortness of breath, rapid heartbeat)
• Chest pain or trouble breathing
• Brittle nails
• Sore tongue
• Restless legs syndrome
• Abnormal cravings for non-food items, such as clay or dirt, paper products, or cornstarch (pica)
• Abnormal craving to eat ice (pagophagia)
• Pale skin or a pale color in the tissue that lines the inside of the eyelids 
• Muscle pains
• Reddish or brown urine (autoimmune hemolytic anemia)
• More frequent infections (aplastic anemia)
• More bruising or bleeding than normal (aplastic anemia)

Causes of low red blood cells (anemia) include: 

• Iron deficiency anemia
  • Loss of large amounts of blood: the most common cause of iron deficiency anemia
  • Decreased iron absorption from food: often due to surgery on the stomach or intestines
  • Inadequate dietary iron intake: often seen in developing countries where there is a lack of foods containing iron, though can occur in infants who drink milk without iron 
  • Pregnancy and the postpartum period: women may develop iron deficiency anemia because of the increased iron requirements of the growing fetus and placenta and blood loss during delivery
• Anemia of inflammation or anemia of chronic disease 
  • Caused by a long-term (chronic) medical condition such as diabetes, cancer, chronic infections, or other chronic problems that cause the body to keep iron away from the red blood cells that are being made
  • Patients may or may not have low iron
• Autoimmune hemolytic anemia 
  • Occurs due to problems with the body's immune system in which the immune system mistakenly attacks and destroys red blood cells
  • The cause is often unknown but may be related to: 
    • Infections such as pneumonia and mononucleosis (“mono”)
    • Certain types of cancer, including chronic lymphocytic leukemia (CLL), multiple myeloma, and lymphoma
    • Autoimmune diseases such as lupus 
    • Certain medicines, including some antibiotics
• Aplastic anemia 
  • Caused by damage to bone marrow 
  • Some people are born with damaged bone marrow
  • The cause is often unknown but other causes may include: 
    • Certain medicines
    • Certain chemicals
    • Infections from certain viruses
    • Problems with the body’s immune system

Low red blood cells (anemia) are diagnosed with a medical history, physical examination, and blood tests.

Blood tests used to diagnose low red blood cells (anemia) include: 

• Complete blood count (CBC), which includes: 
  • Red blood cell (RBC) count
  • Hemoglobin (Hgb)
  • Hematocrit (Hct)
  • Mean corpuscular volume (MCV, referring to RBC size)
  • Mean corpuscular hemoglobin (MCH, referring to the amount of hemoglobin per RBC)
• Serum iron
• Total iron binding capacity (TIBC or transferrin) 
• Transferrin saturation (TSAT)
• Ferritin

For aplastic anemia, tests may also include a bone marrow biopsy.

Treatment for low red blood cells (anemia) depends on the type of anemia. 

For low red blood cells caused by iron deficiency anemia, the first step is to determine the cause of the low iron.  If low iron is due to blood loss, such as from stomach ulcers or bowel problems, those issues need to be treated

People with iron deficiency anemia need additional iron. Eating foods high in iron is not sufficient. Iron supplementation may be given:

• Orally as pills or liquid
  • Ferrous fumarate 
  • Ferrous sulfate 
  • Ferrous sulfate liquid 
  • Ferrous gluconate 
  • Polysaccharide iron complex 
• Intravenously
  • Given to people who cannot absorb an adequate amount of iron from pills

If iron deficiency anemia is severe, a blood transfusion may be needed. 

For some cases of anemia of inflammation, erythropoietin or erythropoiesis-stimulating agents (ESAs) that help the body produce more red blood cells may be used. 

Autoimmune hemolytic anemia is treated with: 

• Treating the underlying condition such as lupus or CLL
• Medications
  • Prednisone, to reduce the body’s immune activity 
  • Cyclophosphamide (Cytoxan) or rituximab (Rituxan) if prednisone does not work well 
• Blood transfusions
• Removal of the spleen (splenectomy)

Treatment for aplastic anemia depends on the cause and may include: 

• Stopping medicines that caused the problem
  • Never stop taking a prescribed medication without first talking to your doctor
• Avoiding toxic chemicals
• Medications
  • Antibiotics 
  • Antiviral medicines
  • Immunosuppressive medicines
• Transfusion of red blood cells or platelets
• Bone marrow transplant (also called a “stem cell transplant”)