A sample containment apparatus, comprising: a unitary chamber body having a first and second engaging end and a hollow interior portion shaped to accommodate a flexible sleeve having a central portion attached to exterior protruding end portions, so that when the flexible sleeve is seated within the hollow interior portion of the chamber body the central portion and the end portions are entirely contained within the hollow interior portion; end plugs shaped to fit within outer ends of the hollow interior portion and an interior portion of the flexible sleeve, each of the end plugs having an orifice configured to enable fluid conduction along a path substantially parallel to a longitudinal axis of the chamber body, the path including an inlet of the apparatus, each orifice, and an outlet of the apparatus; a port to pass through a wall of the chamber body and to couple pressure imposed external to the chamber body to the hollow interior portion when the chamber body is sealed against the pressure; and a first and second engaging end cap to engage the first and second engaging end of the chamber body and to provide the inlet and the outlet; characterised in that the hollow interior portion of the chamber body comprises conformal depressions, wherein the protruding end portions of the sleeve are arranged to fit into the conformal depressions when the sleeve is seated within the body; and further characterised in that when the sleeve is seated, the exterior protruding end portions of the sleeve are arranged as a fluid-tight seal against a wall of the hollow interior portion of the unitary chamber body by the end plugs. a unitary chamber body having a first and second engaging end and a hollow interior portion shaped to accommodate a flexible sleeve having a central portion attached to exterior protruding end portions, so that when the flexible sleeve is seated within the hollow interior portion of the chamber body the central portion and the end portions are entirely contained within the hollow interior portion; end plugs shaped to fit within outer ends of the hollow interior portion and an interior portion of the flexible sleeve, each of the end plugs having an orifice configured to enable fluid conduction along a path substantially parallel to a longitudinal axis of the chamber body, the path including an inlet of the apparatus, each orifice, and an outlet of the apparatus; a port to pass through a wall of the chamber body and to couple pressure imposed external to the chamber body to the hollow interior portion when the chamber body is sealed against the pressure; and a first and second engaging end cap to engage the first and second engaging end of the chamber body and to provide the inlet and the outlet; characterised in that the hollow interior portion of the chamber body comprises conformal depressions, wherein the protruding end portions of the sleeve are arranged to fit into the conformal depressions when the sleeve is seated within the body; and further characterised in that when the sleeve is seated, the exterior protruding end portions of the sleeve are arranged as a fluid-tight seal against a wall of the hollow interior portion of the unitary chamber body by the end plugs.