A blood smear is a laboratory technique used to examine blood cells under a microscope. A small drop of blood is spread thinly on a glass slide, then stained to highlight different cell types. This allows for the assessment of red blood cells, white blood cells, and platelets, helping to identify various medical conditions. The analysis of a blood smear can reveal abnormalities such as infections, anemia, or blood disorders like leukemia. It is a valuable tool for doctors to diagnose and monitor health issues, providing insights into a patient's overall blood health.