Non-invasive radio frequency medical fluid level and volume detection system and method

A medical fluid system comprising:

• a medical fluid pump;
• a container in fluid communication with a medical fluid pump, the container at a first time holding a first fluid having a first conductivity, the container at a second time holding a second fluid having a second conductivity;
• and
• a radio frequency level sensor positioned in operable relation with the container, the radio frequency operation of the level sensor configured so as to be (i) indicative of a level or volume of the first or second fluid in the container and (ii) at least substantially independent of the first and second conductivities.

A medical fluid system comprising:

• a medical fluid pump;
• a container holding a fluid to be pumped by the medical fluid pump;
• and
• a radio frequency sensor operable with the container, the sensor including an emitting electrode and a receiving electrode positioned such that a radio frequency transmission between the emitting electrode and the receiving electrode is affected by an amount of air in the container having a dielectric constant ∈o and an amount of fluid in the container having a dielectric constant ∈d, the container at a first time holding a first fluid and at a second time holding a second fluid having a different conductivity then the first fluid, the first and second fluids having at least substantially the same dielectric constant ∈d, the sensor outputting an impedance signal indicative of an equivalent dielectric constant ∈, the equivalent dielectric constant ∈ based on the dielectric constants ∈o and ∈d.

A medical fluid method comprising:

• pumping a first fluid having a first conductivity from a container;
• pumping a second fluid having a second different conductivity from the container;
• and
• sensing a level or volume of the first and second fluids using a radio frequency transmission that is independent of fluid conductivity.