From the Guidelines
The diagnostic approach for anemia should start with a complete blood count (CBC) and peripheral blood smear, followed by iron studies, vitamin B12 and folate levels, and tests for hemolysis, as recommended by the most recent and highest quality study 1. The initial step in diagnosing anemia involves ordering a CBC with differential and reticulocyte count, as well as reviewing the peripheral blood smear.
- The CBC provides information on red cell size and hemoglobin content,
- while the peripheral smear can reveal morphological abnormalities. The next step is to check iron studies, including serum iron, total iron-binding capacity (TIBC), and ferritin, to diagnose iron deficiency.
- Additionally, measuring vitamin B12 and folate levels can help identify megaloblastic anemias.
- Testing for hemolysis, including lactate dehydrogenase (LDH), haptoglobin, and bilirubin, is also crucial for detecting increased red cell destruction. If the cause of anemia remains unclear, further laboratory tests may be necessary, such as bone marrow biopsy or endoscopy to identify gastrointestinal bleeding sources, as suggested by 1 and 1. However, the most recent and highest quality study 1 recommends a more streamlined approach, focusing on CBC, iron studies, and tests for hemolysis. The minimum workup should include complete blood count with MCV, reticulocytes, serum ferritin, transferrin saturation, and CRP, as stated in 1. This approach helps differentiate between common causes of anemia, such as iron deficiency, B12/folate deficiency, and chronic disease, and rarer forms, such as hemolytic anemia and thalassemia. By following this diagnostic approach, clinicians can effectively identify the underlying cause of anemia and provide targeted treatment to improve patient outcomes.
From the Research
Diagnostic Approach for Anemia
The diagnostic approach for anemia involves a combination of laboratory tests and physical examinations to determine the underlying cause of the condition. The following steps are typically taken:
- Initial evaluation consists of a thorough history and physical examination and a complete blood cell count (CBC) 2
- Careful examination of the CBC and the mean corpuscular volume provides important clues to the classification and cause of anemia 2
- Supplemental tests may include a peripheral blood smear; reticulocyte count; iron panel (ie, ferritin and iron levels, total iron-binding capacity, transferrin saturation); and levels of vitamin B12, folate, lactate dehydrogenase, haptoglobin, and bilirubin 2
Laboratory Tests
Laboratory tests play a crucial role in the diagnosis of anemia. The following tests are commonly used:
- Complete blood count (CBC) to determine hemoglobin levels, hematocrit, and red blood cell count 3, 4, 5, 2
- Reticulocyte count to determine the number of immature red blood cells in the blood 3, 4, 5, 6
- Peripheral smear evaluation to examine the morphology of red blood cells 3, 2
- Iron parameters, such as ferritin and iron levels, to diagnose iron deficiency anemia 3, 2, 6
- Hemoglobinopathies/thalassemia evaluation in microcytic hypochromic anemia 3
- Vitamin B12 and folic acid level in macrocytic anemia 3, 2
Algorithmic Approach
An algorithmic approach can be used to analyze the cause of anemia based on laboratory test results. This approach can help to:
- Determine the probable etiology of anemia based on mean corpuscular volume, red cell distribution width, and reticulocyte count 4
- Automatically order reflex tests needed to confirm the diagnosis 4
- Provide a practical and simplistic approach to the diagnosis of anemia, focusing on basic parameters such as CBC, reticulocyte count, and peripheral smear 3