My bad, glucagon (often with K+) is used IV when hypo. Reading and not thinking... sry -.- Only an r-tard would give insulin to a hypo patient.
...Though doesn't make my technique point mute.
SC: there is no need for aspiration nor aseptic technique; IM different story. If SC or IV was just as effective, it would be done. If you aspirate blood when IM, you have nicked a vein or may be in it and need to re-place your needle (no need to change at this point).