Anemia definition
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Anemia Definition and Key Diagnostic Criteria
Anemia is defined as a condition where there is a decrease in the concentration of hemoglobin or the number of red blood cells (RBCs) in the blood, resulting in a reduced ability of the blood to carry oxygen to the body's tissues Marineci2019Chen2019Guevara-Ríos2024+6 MORE. This reduction in oxygen transport can affect vital functions and lead to symptoms such as fatigue, pallor, and shortness of breath, especially when hemoglobin levels fall below certain thresholds Guevara-Ríos2024Mutlaq2024.
Hemoglobin Thresholds and WHO Criteria
The World Health Organization (WHO) defines anemia based on hemoglobin (Hb) levels: less than 13.0 g/dL in men and less than 12.0 g/dL in women Cappellini2015Izaks1999Milovanović2021. For pregnant women, the threshold is typically set at less than 11.0 g/dL, and for the elderly, some guidelines use less than 12.0 g/dL for both sexes Chen2019Cappellini2015. These values can vary slightly depending on age, sex, ethnicity, and geographic location, such as altitude Chen2019Cappellini2015Milovanović2021.
Causes and Pathophysiology of Anemia
Anemia is not a disease itself but a symptom of various underlying conditions. The main causes include:
- Blood loss (e.g., from injury or menstruation)
- Decreased RBC production (due to deficiencies in iron, vitamin B12, or folic acid)
- Increased RBC destruction (hemolysis) Marineci2019Cappellini2015Mutlaq2024+2 MORE
Chronic diseases, inflammation, kidney disease, and certain medications can also contribute to anemia Marineci2019Cappellini2015Mutlaq2024+2 MORE.
Clinical Evaluation and Diagnosis
Diagnosis of anemia involves measuring hemoglobin and RBC counts using automated instruments. Additional tests, such as reticulocyte counts, peripheral blood smears, and assessments for underlying causes, are often necessary Chen2019Mutlaq2024Milovanović2021. Clinical evaluation includes a thorough history, physical examination, and sometimes imaging or specialized laboratory tests Mutlaq2024Milovanović2021.
Global Prevalence and Impact
Anemia is a widespread health issue, affecting about one-third of the global population. It is especially common among women of reproductive age, children, and the elderly, with the highest prevalence in low- and middle-income countries Mutlaq2024Ismail2024. The condition can impact cognitive development, economic productivity, and overall well-being .
Conclusion
Anemia is a condition marked by reduced hemoglobin or red blood cell levels, leading to decreased oxygen delivery to tissues. It is diagnosed based on specific hemoglobin thresholds that vary by age, sex, and other factors. Anemia is a common and multifactorial health problem, often reflecting underlying nutritional deficiencies, chronic diseases, or other medical conditions. Early recognition and targeted management are essential for improving health outcomes.
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