Erythropenia, also known as erythrocytopenia, refers to a lower-than-normal level of red blood cells (erythrocytes) in the bloodstream. This condition can lead to anemia, characterized by symptoms such as fatigue, weakness, and paleness due to reduced oxygen-carrying capacity. Erythropenia can result from various causes, including bone marrow disorders, chronic diseases, nutritional deficiencies, or blood loss. Diagnosis typically involves blood tests and may require further investigation to identify the underlying cause.