Most hospital protocols will outline for you what gauge of IV needles you can use for blood product administration. Some hospitals allow you to use 20 or 22 gauge IV needles in the adult population, however, some do not and may require a central line.What size needle is used for IV?
The smaller the gauge number, the larger the diameter of the needle. A 16-gauge needle is larger than a 24-gauge needle. The type of intravenous (IV) therapy that is ordered can determine the size of IV catheter that is needed. For example, a blood transfusion requires an 18- or 20-gauge needle.