Abstract: A body fluid meter assembly for measuring diuresis including a body fluid collection container configured to collect body fluid such as urine, a body fluid meter unit including a load cell and a coupling mechanism configured to releasably couple the collection container to the load cell, which body fluid meter unit is configured to process sensor data supplied by the load cell and derive a measurement of a quantity and/or flow rate of the body fluid in the collection container as a function of load applied on the load cell, and tubing attached to an inlet port of the collection container and configured to be connected to a source of the body fluid. The collection container is a substantially rigid container and the coupling mechanism is a spring-loaded interlocking mechanism configured to cooperate with one or more interlocking members to interlock with the collection container to form a stable connection.