Is Blood a Drug?

Yes! At least as defined by the Food and Drug Administration. In this very long section the FDA explains...

"The term "drug" means (A) articles recognized in the official United States Pharmacopoeia,1 official Homoeopathic Pharmacopoeia of the United States, or official National Formulary, or any supplement to any of them; and (B) articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals; and (C) articles (other than food) intended to affect the structure or any function of the body of man or other animals; and (D) articles intended for use as a component of any article specified in clause (A), (B), or (C)."

Based on this definition, blood, in the eyes of the FDA, is indeed a drug! That would explain why Blood Bank's are inspected by the FDA and must report exceptions/occurrences/and errors as soon possible. It's no wonder Blood Banks across the country are very adamant for clinicians to ensure there is a physicians order behind every product transfused. You wouldn't give a patient medication without a prescription, thus nor will a transfusion service provide blood products without a physicians order. This is true even in emergent situations. Doctors will have to sign off agreeing to give uncrossmatched blood. Usually on a paper provided by the blood bank. MTP activations generally require the activating physician to be noted as well. No prescription? No blood. It's federal law. 

There is an inherent risk to transfusing blood despite all pre-analytical, analytical, and post-analytical attempts at donor/patient safety, beginning before the blood donor even has their phlebotomy. This is where the FDA comes in. They oversee and regulate the entire blood supply across the United States, from beginning to end. From patient questionnaires/interview prior to donation to regular transfusion service inspections and mandations that if ANY of the regulations/rules/requirements during these stages were not met, it must be reported to the FDA. For example, if a patient required irradiated blood products but this requirement was somehow missed and the patient was transfused with NON-irradiated blood products, the FDA must be made aware of this occurrence.