Brilliant Cresyl Blue ALD is widely used in biological and medical research as a vital stain. It is particularly effective in staining reticulocytes, which are immature red blood cells, allowing for their identification and counting in blood samples. This application is crucial in diagnosing and monitoring conditions like anemia and bone marrow function. Additionally, it is employed in histology to differentiate and highlight specific cellular components in tissue samples. The dye is also utilized in microbiology for staining live cells, aiding in the study of cell viability and proliferation. Its ability to selectively stain certain structures makes it a valuable tool in both clinical and research laboratories.