Annexin Binding Buffer is used in flow cytometry procedures to facilitate binding between annexin structures and apoptotic cells. Annexins belong to a group of proteins with calcium-dependent binding characteristics, which bind in high-calcium environments. Annexin Binding Buffer provides an isotonic and high-calcium environement with stable pH to promote annexin binding. This buffer is provided at a 5X concentration and is ready-to-use once diluted to a 1X working concentration.