An automatic analysis system for in vitro diagnostics, comprising: - a plurality of reaction cuvettes each comprising a base and intended to contain biological liquids samples to analyze, - a storage device configured to store the plurality of reaction cuvettes , - at least one samples processing station , comprising at least one receiving cavity configured to receive and house at least partially one reaction cuvette , the at least one receiving cavity comprising a lower introduction opening which opens downward and which is configured to enable the introduction of a reaction cuvette into the at least one receiving cavity, and - a displacement device configured to displace a reaction cuvette , the displacement device being further configured to unload a reaction cuvette out of the storage device and to load and unload a reaction cuvette into and out of the at least one receiving cavity of the at least one samples processing station via the respective lower introduction opening , the displacement device being disposed under the at least one samples processing station and comprising: - a first support element movably mounted according to a first direction of displacement (D1) which is substantially horizontal, - a second support element movably mounted on the first support element according to a second direction of displacement (D2) which is substantially horizontal and whish is substantially orthogonal to the first direction of displacement (D1), and - a drive member movably mounted on the second support element according to a third direction of displacement (D3) which is substantially vertical, the drive member being configured to cooperate with the base of a reaction cuvette and to transmit a drive movement to said reaction cuvette . - a plurality of reaction cuvettes each comprising a base and intended to contain biological liquids samples to analyze, - a storage device configured to store the plurality of reaction cuvettes , - at least one samples processing station , comprising at least one receiving cavity configured to receive and house at least partially one reaction cuvette , the at least one receiving cavity comprising a lower introduction opening which opens downward and which is configured to enable the introduction of a reaction cuvette into the at least one receiving cavity, and - a displacement device configured to displace a reaction cuvette , the displacement device being further configured to unload a reaction cuvette out of the storage device and to load and unload a reaction cuvette into and out of the at least one receiving cavity of the at least one samples processing station via the respective lower introduction opening , - a first support element movably mounted according to a first direction of displacement (D1) which is substantially horizontal, - a second support element movably mounted on the first support element according to a second direction of displacement (D2) which is substantially horizontal and whish is substantially orthogonal to the first direction of displacement (D1), and - a drive member movably mounted on the second support element according to a third direction of displacement (D3) which is substantially vertical, the drive member being configured to cooperate with the base of a reaction cuvette and to transmit a drive movement to said reaction cuvette . <EOS>