An IV infusion is when a medical professional inserts a needle into your vein in order to give you fluids, medicine, or blood. An IV infusion can be used for therapy, prophylaxis, or diagnosis. An IV infusion for therapy means that the IV is being used to treat a medical condition. An IV infusion for prophylaxis means that the IV is being used to prevent a medical condition. An IV infusion for diagnosis means that the IV is being used to help diagnose a medical condition. An IV infusion for additional infusions means that the IV is being used for more than one purpose.