From the Guidelines
The white blood cell count (WBC) does not typically decrease with severe anemia, as anemia is a condition characterized by a reduction in red blood cells or hemoglobin, while the WBC count reflects the immune system's status and is generally independent of anemia. In fact, in some cases of severe anemia, particularly those caused by hemolysis (destruction of red blood cells) or acute blood loss, the WBC count may actually increase as part of the body's stress response 1. The bone marrow, which produces all blood cells, can selectively increase or decrease production of specific cell lines. Therefore, a low red blood cell count does not necessarily affect white blood cell production.
When evaluating a patient with severe anemia, it is essential to consider the potential causes of anemia, such as iron deficiency, which is common in patients with chronic kidney disease 1. Iron deficiency can be diagnosed by measuring serum iron and total iron-binding capacity (TIBC), and treating iron deficiency can improve or correct anemia. However, the WBC count should be assessed separately as it provides important information about potential infections or other underlying conditions.
Some key points to consider when evaluating a patient with severe anemia include:
- The severity of anemia on admission is associated with increased morbidity and mortality in critical care patients 1
- Anemia can persist in the medium- and long-term, and a large proportion of critical care patients are exposed to blood transfusion 1
- The WBC count can increase in response to stress, such as in cases of severe anemia caused by hemolysis or acute blood loss
- A low WBC count (leukopenia) in a patient with severe anemia suggests either bone marrow failure affecting multiple cell lines, a specific disease process, or medication effect that is impacting both cell types independently.
In summary, when managing a patient with severe anemia, it is crucial to assess the WBC count separately and consider the potential causes of anemia, as well as the potential impact of anemia on morbidity and mortality. The WBC count should not be expected to decrease with severe anemia, and any changes in the WBC count should be evaluated in the context of the patient's overall clinical condition.
From the Research
WBC Count in Severe Anemia
- The relationship between white blood cell (WBC) count and severe anemia is complex and can be influenced by various factors, including the underlying cause of anemia and the presence of inflammation or infection 2, 3.
- A study published in the Indian Journal of Physiology and Pharmacology found that total leucocyte count (TLC) was insignificantly higher in anemic subjects compared to controls, while differential count showed higher neutrophils and basophils, and lower eosinophils and monocytes 2.
- Another study published in Blood discussed anemia of inflammation, which is a common type of anemia in hospitalized and chronically ill patients, and noted that inflammation-inducible cytokines and hepcidin can affect iron homeostasis and erythropoiesis, leading to anemia 3.
- The Medical Clinics of North America published an article on the evaluation and diagnostic tests for anemia, which highlighted the importance of complete blood count with red cell indices, reticulocyte count, and examination of the bone marrow in determining the etiology of anemia 4.
- A study published in Clinics in Chest Medicine discussed critical issues in hematology, including anemia, thrombocytopenia, and coagulopathy in critically ill patients, and noted that WBC count can be affected by various factors, including infection, inflammation, and medication 5.
- Elevated leukocyte count has been linked to systemic inflammation, disease progression, and poor prognosis, particularly in older adults, and can be a harbinger of increased cardiovascular and noncardiovascular mortality 6.
Key Findings
- WBC count can be affected by severe anemia, but the relationship is complex and influenced by various factors.
- Inflammation and infection can increase WBC count, while certain types of anemia, such as anemia of inflammation, can decrease WBC count.
- Diagnostic tests, including complete blood count and bone marrow examination, are essential in determining the etiology of anemia and guiding treatment.
- Elevated leukocyte count can be a marker of systemic inflammation and poor prognosis, particularly in older adults.