Abstract: An in vitro diagnostic analyzer and a reagent card. The reagent card includes a reagent card body and a mounting body. The mounting body includes a mounting hole configured to be sleeved on receive a sample tube, a hollow needle disposed in the mounting hole, a sealing portion disposed in the mounting hole, and a gas inlet channel. An end of the hollow needle is capable of being inserted into the sample tube. The sealing portion is capable of being in sealing fit with an outer wall of the sample tube. The gas inlet channel includes a gas outlet hole, a gas inlet hole, and a first flow-stopping structure. The gas inlet hole is disposed in a surface of the reagent card body. The first flow-stopping structure is disposed between the gas outlet hole and the gas inlet hole. The gas outlet hole is configured to be in fluid communication with the sample tube mounted on the mounting hole. The reagent card body includes a sample feeding channel, a test chamber, and a venting end.