Low absolute monocyte counts, known as monocytopenia, can be caused by various factors and conditions. Some possible causes include certain medications (such as corticosteroids and chemotherapy drugs), bone marrow disorders, viral infections (such as HIV), severe bacterial infections, overwhelming sepsis, and certain autoimmune disorders. Additionally, congenital or inherited conditions can also lead to low monocyte counts. Determining the underlying cause of low absolute monocytes requires a thorough evaluation by a healthcare professional, including a detailed medical history, physical examination, and additional diagnostic tests. Treatment will depend on addressing the specific underlying cause and may involve medications, lifestyle modifications, or other interventions as appropriate.