Is acid fast stain used to detect cryptosporidium protozoa in fecal samples? how does it work?

Yes: Yes acid fast stain is useful for identifying mycobacteria, since their cell walls contain large amount of lipid substances, which are very visible under acid-fast stain. What specifically were you wondering about? Hope that helps.

Cryptosporidiosis: Yes. As stated earlier there are acid-fast lipids in oocyst walls of cryptosporidium that picks up stain and can be seen microscopically.Cryptosporidium can be assessed via acid-staining test of stool or biopsied intestinal tissue & enzyme immunoassays for antigens. There is also Cryptosporidium/isospora stool study & Giardia & Cryptosporidum Antigen Panel