A fitting element is configured for coupling tubing to a fluidic device having a receiving cavity configured for receiving the fitting element, where the tubing has an inner contact surface of a biocompatible material, the inner contact surface being configured to contact a fluid to be conducted by the tubing, and the receiving cavity having a receiving contact surface of a bio-compatible material. The fitting element includes a first sealing element of a bio-compatible material configured for sealing to the bio-compatible material of the inner contact surface of the tubing, and a second sealing element configured for sealing against a pressure ambient to a pressure of the fluid in the tubing. Upon coupling of the tubing to the fluidic device, at least a portion of the receiving contact surface, the first sealing element, and the second sealing element enclose an interspace, each surface of the interspace being a bio-compatible material.