Abstract: A fluid testing and analysing device and a method therefor are described. The device includes, from its base up and in its upstanding configuration, a tube-holder (A) for receiving at least one partially or totally transparent tube (1) so that one wall or part of a wall thereof is visible; one or more tubes (1) forming a closed testing and observation chamber, closure means (4) for each tube, with a needle (3) extending therethrough and a flange (5), surrounding the needle, of smaller diameter than the closure means; a substantially vertical raised portion forming peripheral and/or internal walls surrounding the needles (3) and advantageously higher than the distance by which the needles project above the closure means (4); and, optionally, perforatable sheathes (11) placed on the portion outside the closed chamber (1). The device is particularly useful for human and animal biology applications.