A test tube (10) for taking and containing a sample for diagnostic analyses comprises a containing body (12) with an end edge (11a) that delimits an aperture (11), a tubular member (22) protruding toward the outside with respect to said end edge (11a) and connected with the inside of said containing body (12) through said aperture (11) for the passage of the sample, suction means (13, 115) made in a single piece with said containing body (12) and selectively drivable to take in a desired volume of sample through said tubular member (22), a closing device (14) constrained to said end edge (11a) and comprising a closing element (18) selectively movable toward a closing position located above said end edge (11a) in order to close said aperture (11). The tubular member (22) is conformed to be selectively removable so as to allow the passage of the closing element (18) to the superimposed position, in order to close the aperture (11).
