What defines anemia in adults?

• A. Excess of red blood cells
• B. Decrease in hemoglobin or red blood cells
• C. Increase in platelet count
• D. Normal hemoglobin levels but low iron

Answer: (B)

Anemia in adults is primarily defined as a decrease in hemoglobin concentration or a reduction in the number of red blood cells. Hemoglobin is responsible for carrying oxygen from the lungs to the rest of the body, and a reduction in its levels can lead to insufficient oxygen delivery to tissues, resulting in various clinical symptoms such as fatigue, weakness, and pallor. Anemia can occur due to several reasons, including blood loss, decreased production of red blood cells, or increased destruction of red blood cells.

The other options do not accurately characterize anemia: an excess of red blood cells defines polycythemia rather than anemia, an increase in platelet count relates to thrombocytosis which is a different hematological condition, and normal hemoglobin levels with low iron may indicate iron deficiency without actual anemia if hemoglobin levels are not affected yet. Therefore, the defining characteristic of anemia is indeed the decrease in hemoglobin or red blood cell count.