It used to be that AABB accreditation meant you achieved a level of sophistication encompassing Quality System Essentials. Today, I am not certain that is the case. CAP has deemed status and has upgraded their standards to be at least as stringent as AABB's (some are even more so). Probably the only selling point are the CE materials and the national meeting every year. Hospitals I have worked in have all been AABB accredited. My current employer, we dropped AABB about 15 years ago because there wasn't any bang for the buck to be accredited by them. This was my decision - was an AABB member and assessor/inspector for 20+ yrs.