An apparatus (120) for collecting blood in a container and connecting it to an intravenous tube, comprising: a main body (121.1) that defines an interior and includes a collection cavity adapted and configured to receive inside one end of a container easily separable； a first retractable hollow needle (140) having a first sharp point, said first needle moving from a first extended position in which the first sharp point is external to said main body for insertion into a blood vessel to a second position retracted in which the first sharp point is within a portion of the interior； a second hollow needle (152) attached to said main body and having a second sharp point extending into the collection cavity； a catheter assembly (130) having a hollow body and lumen and receiving said first needle into the lumen, the first sharp point extending from the distal end of the lumen； and a gas purge valve (58) supported by said main body allowing the escape of the gas contained in a fluid flow path from said first needle to said second needle； wherein said first needle is easily detachable from said catheter assembly, said first needle automatically retracts to the second position in response to the separation of said first needle from said catheter assembly, and the collection cavity maintains a fixed relationship in relation to to the interior portion in both the first position and the second position.Un aparato (120) para recolectar sangre en un contenedor y conectarlo a un tubo intravenoso, que comprende: un cuerpo principal (121.1) que define un interior e incluye una cavidad de recolección adaptada y configurada para recibir en su interior un extremo de un contenedor fácilmente separable； una primera aguja hueca retráctil (140) que tiene una primera punta afilada, que es móvil dicha primera aguja desde una primera posición extendida en la que la primera punta afilada es exterior a dicho cuerpo principal para su inserción en un vaso sanguíneo a una segunda posición retraída
