Giving insulin and other potentially hazardous drugs to patients requires a heightened level of inspection. Current practice requires that nurses double check the dose of insulin to be given with another nurse, even after the nurse has double checked his or her own calculations. This level of inspection is considered warranted because of the risks of over- or under-dosing. However, for less hazardous medications, no second double check is needed. When blood is administered to patients, the level of inspection is increased. Double checks occur three times: when the blood is prepared in the blood bank, when it is signed out to the patient unit, and when it is administered to the patient.