A fluidic centripetal apparatus for testing components of a biological material in a fluid is presented. The fluidic centripetal device is adapted to be received within a rotatable holder. The apparatus comprises a fluidic component layer having fluidic features on at least a front face and a bottom component layer bonded to a rear of the fluidic component layer thereby creating a fluidic network through which the fluid flows under centripetal force. In one embodiment, the fluidic feature may be a bottom-fillable chamber coupled to an entry channel for receiving the fluid, the chamber inlet being provided at an outer side of the bottom-fillable chamber. In another embodiment, the fluidic feature may be a retention chamber coupled to an entry channel for receiving the fluid, a container wholly provided in the retention chamber and containing a liquid diluent, the container maintaining the liquid diluent in the container until it releases it in the retention chamber upon application of an external force to the container, thereby restoring the fluidic connection between the liquid diluent and the fluid in the retention chamber. Additionally, the retention chamber can have a flow decoupling receptacle for receiving the fluid, located at the outer side of the retention chamber and interrupting a fluidic connection between the entry and exit of the retention chamber. A test apparatus and a testing method using a fluidic centripetal device for testing components of a biological material in a fluid are also provided.