Buffer for use with the BioVision’s Annexin V-FITC (Cat.# 1001-1000), Annexin V-Cy3 (Cat.# 1002-1000), Annexin V-Cy5 (Cat.#1013-1000), Annexin V-EGFP (Cat.# 1004-1000), Annexin V-PE (1014-1000), Annexin V-Biotin (Cat.# 1003-100), and Unlabeled Anenxin V (Cat.# 1005-100) reagents. During apoptosis, phosphatidylserine (PS) is translocated from the cytoplasmic face of the plasma membrane to the cell surface. Annexin V has a strong, Ca²ᶧ-dependent affinity for PS and therefore serves as a probe for detecting apoptosis.