I didn't vote because we use a combination of the above options. If we have a sample in the lab (usually a cbc) labeled to meet blood bank requirements we will use that specimen for confirmation. If there is no specimen we have a sample drawn to confirm the blood type. If none of these are possible we will transfuse with type O until a second sample can be obtained. That doesn't happen often, and usually we have a sample in the lab so redraws are limited.