Once you have scruffed the neck, gently turn your hand over so the rat is lying comfortly in the palm of your hand. Do not squeeze the rat around the thorax region because that could cause difficulty breathing. Make sure the rat’s body is straight and not bent or curled in your palm.
Have other technician wipe down the shaved area with an alcohol swab.
With your other hand, use index finger to lightly hold head. Do not put to much pressure on rats head or neck. With thumb, apply slight pressure on vein proximal to the collection site so it will distend. This will make the jugular vein more prominent for easier visualization. The bottom half of rat is still just resting in palm of hand.
Have the technician drawing blood get the syringe and needle ready. We use a 1 ml syringe with a 23 gauge needle.
Insert needle through skin right around the middle point between the sternum and shoulder area, where you should see the vein. Advance slowly. Create a slight vacuum within the syringe, while advancing your needle.
Once you hit the vein, a small drop of blood will leak into the hub of the needle. Try not to let your syringe move around and keep drawing back on the plunger. Do not pull back too fast because it might cause the vein to collapse.