Abstract: A method for transferring a fluid sample from a first chamber to a second chamber separated from the first chamber involves opening a closed cavity defined between the end portions of two coaxially arranged cylindrical rods while in the first chamber, then closing the open cavity in the first chamber to enclose the fluid sample, transferring the closed cavity from the first chamber to the second chamber by effecting axial movement of the rods relative to the chambers, then opening the closed cavity in the second chamber to allow the fluid sample to enter the second chamber. A device for carrying out this method is provided with first and second rods arranged to move along a common axis, the device including an arrangement for effecting displacement of the rods relative to each other and relative to the chambers or displacement of the rods together while the end portions of the rods are in contact to effect transfer of the fluid sample from one chamber to the other.