A mechanically-actuated vacuum-controlled fluid collection system includes a mechanically-actuated vacuum controller (MAVC) to draw fluid into a chamber through the opening to the chamber. The system may include a releasable seal to seal the opening, and the MAVC may include a spring-loaded plunger to create a vacuum within the chamber when sealed. The system includes multiple fluid chambers, and may further include a single actuator or multiple corresponding actuators. The system may be configured to add a pre-loadable reagent to fluid drawn into the one or more chambers, and may be configured to add the reagent in proportion to a volume of the fluid. The system may be controllable to release collected fluid to another device, such as for assay and/or transport. The system may be configured to draw a liquid biological sample such as urine, and may include a fluid interface to draw fluid from a biological sample container.