what size needle does a tb test use
Youâll use intermediate strength (5 T.U.) PPD in a tuberculin syringe that has a 1/2-inch, 26- or 27-gauge needle. Make sure the bevel edge of the needle is facing up, and insert the needle beneath the skin (Figure 1).ouâll use intermediate strength (5 T.U.) PPD in a tuberculin syringe that has a 1/2-inch, 26- or 27-gauge needle. Make sure the bevel edge of the needle is facing up, and insert the needle beneath the skin (Figure 1).