Used for detecting apoptosis in cells through flow cytometry or fluorescence microscopy. The kit distinguishes between live, early apoptotic, late apoptotic, and necrotic cells. Annexin V binds to phosphatidylserine exposed on the outer membrane of apoptotic cells, while FITC fluorescence marks these cells in green. Propidium iodide (PI) stains dead cells with compromised membranes, showing red fluorescence. This dual staining allows clear differentiation of cell death stages, making it valuable in cancer research, drug development, and toxicology studies to assess treatment-induced apoptosis.