How do you draw blood from a midline?

Midlines are notorious for not being able to obtain blood return. Not sure why though. Flush with saline first, then pull back your waste and discard. Attach new sterile 10cc syringe and withdraw required amount of blood you need for your specific lab tests. Then flush lune again with saline.
Sometimes you have to try flushing with 2-3 10cc saline syringes first before you get a blood return. If that fails, use a butterfly or place a PIV in another vein for your blood draw.