 A standard dose of 5 tuberculin units (TU - 0.1 ml), according to the CDC, or 2 TU of Statens Serum Institute (SSI) tuberculin RT23 in 0.1 ml solution, according to the NHS, is injected intradermally (between the layers of dermis) and read 48 to 72 hours later.This intradermal injection is termed the Mantoux technique.A person who has been exposed to the bacteria is expected to mount an immune response in the skin containing the bacterial proteins.