What is the evaluation for new onset severe persistent anemia (low red blood cell count)?

From the Guidelines

For a new evaluation of severe persistent anemia, I recommend a comprehensive approach starting with a complete blood count (CBC) with differential, peripheral blood smear, reticulocyte count, iron studies (ferritin, transferrin saturation, total iron binding capacity), vitamin B12 and folate levels, and a comprehensive metabolic panel. This approach is based on the most recent and highest quality study available, which emphasizes the importance of a thorough evaluation to determine the underlying cause of anemia 1.

Key Components of the Evaluation

• Complete blood count (CBC) with differential to assess the severity of anemia and identify any underlying hematological disorders
• Peripheral blood smear to evaluate the morphology of red blood cells and detect any abnormalities
• Reticulocyte count to assess the bone marrow's response to anemia
• Iron studies, including ferritin, transferrin saturation, and total iron binding capacity, to evaluate iron deficiency or overload
• Vitamin B12 and folate levels to assess for deficiencies that may be contributing to anemia

Additional Testing

• Hemolysis markers, such as haptoglobin, LDH, and bilirubin, to evaluate for hemolytic anemia
• Inflammatory markers, such as CRP and ESR, to assess for chronic inflammation
• Hemoglobin electrophoresis to evaluate for hemoglobinopathies
• Testing for occult blood loss, such as fecal occult blood testing, endoscopic evaluation, and assessment of menstrual blood loss in women of reproductive age

Treatment

• Blood transfusion may be required for severe anemia (hemoglobin below 7 g/dL) or symptomatic patients (chest pain, dyspnea, tachycardia)
• Iron deficiency anemia typically requires oral ferrous sulfate 325 mg three times daily or ferrous gluconate 325 mg twice daily for 3-6 months
• Vitamin B12 deficiency requires cyanocobalamin 1000 mcg daily orally or intramuscularly for one week, then weekly for one month, then monthly

This comprehensive approach is essential to determine the underlying cause of anemia and provide appropriate treatment, as severe persistent anemia can indicate serious underlying conditions, including malignancy, chronic inflammation, or organ dysfunction, and can lead to cardiac complications if left untreated 1.

From the FDA Drug Label

Evaluate iron status before and during treatment and maintain iron repletion. Correct or exclude other causes of anemia before initiating treatment ( 2.1). If severe anemia and low reticulocyte count develop during PROCRIT treatment, withhold PROCRIT and evaluate for PRCA ( 5.6).

The evaluation for new severe persistent anemia should include correcting or excluding other causes of anemia before initiating treatment with epoetin alfa (IV) 2. Additionally, if severe anemia and low reticulocyte count develop during treatment, epoetin alfa (IV) should be withheld and evaluated for Pure Red Cell Aplasia (PRCA) 2 2. Iron status should also be evaluated before and during treatment, and iron repletion should be maintained 2.

From the Research

Evaluation for New Severe Persistent Anemia

• The evaluation of anemia involves a thorough history and physical examination, as well as laboratory tests such as a complete blood cell count (CBC) 3.
• The CBC provides important clues to the classification and cause of anemia, including the mean corpuscular volume (MCV) 3, 4.
• Supplemental tests may include a peripheral blood smear, reticulocyte count, iron panel, and levels of vitamin B12, folate, lactate dehydrogenase, haptoglobin, and bilirubin 3, 4.
• The reticulocyte count serves as a useful screen for hemolysis or blood loss 4.
• Reticulocyte hemoglobin content (CHr) is a good indication of iron availability and an early marker of iron deficient erythropoiesis, and can be used to diagnose iron deficiency and iron deficiency anemia 5.
• CHr has a moderate sensitivity and specificity for diagnosing iron deficiency, and is less affected by inflammation than serum iron, transferrin saturation, and ferritin 5.
• Bone marrow examination may be required for diagnosis in some cases 4.
• Molecular testing is increasingly being used to aid the diagnostic process 4.

Laboratory Markers

• Laboratory markers provide important information for the diagnosis and management of anemia 6.
• Iron panel, including ferritin and iron levels, total iron-binding capacity, and transferrin saturation, can help diagnose iron deficiency and iron deficiency anemia 3, 7.
• Soluble transferrin receptor, serum iron, and transferrin saturation are biomarkers of iron status, but may be affected by inflammation, chronic diseases, and the normal aging process 5.

Diagnosis and Management

• The diagnosis of iron deficiency anemia is still complicated, and most tests have drawbacks 5.
• The term iron deficiency refers to the reduction of total body iron stores due to impaired nutrition, reduced absorption, increased blood loss, and increased needs 7.
• Iron deficiency anemia is defined as low hemoglobin or hematocrit associated with microcytic and hypochromic erythrocytes and low red blood cell count due to iron deficiency 7.
• Treatment of iron deficiency anemia depends on the underlying cause and may include iron supplementation, vitamin B12, and folate 6, 7.