From the Guidelines
Anemia is not only defined by low hemoglobin and hematocrit (H&H) levels, but rather as a haemoglobin (Hb) concentration below the lower limit of normal for the relevant population and laboratory performing the test. According to the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1, this definition is recommended with a strong statement strength and 100% consensus. Anemia is a condition characterized by a reduced number of red blood cells or a decreased ability of the blood to carry oxygen, which can be measured in several ways. While low hemoglobin and low hematocrit are standard diagnostic criteria, other parameters are also important, such as:
- Red blood cell count
- Mean corpuscular volume (MCV)
- Mean corpuscular hemoglobin (MCH)
- Mean corpuscular hemoglobin concentration (MCHC) Additionally, iron studies, vitamin B12, folate levels, and reticulocyte count may be necessary to determine the specific type and cause of anemia, as suggested by the European Consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1. The underlying pathophysiology involves either decreased production of red blood cells in the bone marrow, increased destruction of red blood cells, or blood loss. Therefore, a comprehensive evaluation beyond just H&H is essential for proper diagnosis and treatment of anemia.
The diagnosis of anemia should be based on a combination of clinical evaluation, laboratory tests, and iron studies, as recommended by the British Society of Gastroenterology guidelines 1. A good response to iron therapy, defined as a Hb rise ≥10 g/L within a 2-week timeframe, is highly suggestive of absolute iron deficiency, even if the results of iron studies are equivocal. This approach prioritizes the patient's morbidity, mortality, and quality of life, and is supported by the most recent and highest quality evidence available 1.
From the Research
Definition of Anemia
Anemia is defined as a condition characterized by abnormally low hemoglobin concentration or decreased red blood cells 2, 3. According to the World Health Organization (WHO), anemia is defined as hemoglobin (Hb) levels <12.0 g/dL in women and <13.0 g/dL in men 2.
Diagnosis of Anemia
The diagnosis of anemia is not solely based on low Hemoglobin and Hematocrit (H&H) levels. A thorough evaluation, including:
- A complete blood cell count (CBC) 4, 5
- A complete medical history and physical examination 4, 6
- Laboratory markers, such as mean corpuscular volume, reticulocyte count, and iron panel 4, 5
- Supplemental tests, including peripheral blood smear and molecular testing 5
Classification of Anemia
Anemia can be classified into different types, including:
- Microcytic anemia, which may be due to iron deficiency 3
- Normocytic anemia
- Macrocytic anemia The classification of anemia is important for determining the underlying cause and providing appropriate treatment.
Causes of Anemia
Anemia can be caused by various factors, including:
- Nutritional deficiencies, such as iron, folate, or vitamin B12 deficiency 2
- Chronic diseases, such as anemia of chronic disease 2
- Blood loss or hemolysis 3, 6
- Unexplained anemia, which may be due to a chronic subclinical pro-inflammatory state or resistance of bone marrow erythroid progenitors to erythropoietin 2