Birefringence microscopy,[6] flow cytometry [7] or fluorescence microscopy can be used for assessing the shedding of the acrosome or "acrosome reaction" of a sperm sample. Flow cytometry and fluorescence microscopy are usually done after staining with a fluoresceinated lectin such as FITC-PNA, FITC-PSA, FITC-ConA, or fluoresceinated antibody such as FITC-CD46.[8] The antibodies/lectins have a high specificity for different parts of the acrosomal region, and will only bind to a specific site (acrosomal content/ inner/outer membrane). If bound to a fluorescent molecule, regions where these probes have bound can be visualised.