Biological fluid dilution devices

A biological fluid dilution device, comprising:

• a syringe body comprising a diluent chamber partially filled with a diluent fluid at a front end of the syringe body and a piston tube at a rear end of the syringe body leading into the diluent chamber;
• a moveable piston slidably engaged in the piston tube and forming a fluid-tight seal with an interior surface of the piston tube, wherein the moveable piston comprises a metering groove to contain a precise volume of a biological fluid between the metering groove and the interior surface of the piston tube;
• a biological fluid inlet on the piston tube capable of delivering the biological fluid to the metering groove, wherein the moveable piston is slidable toward the diluent chamber to introduce the biological fluid in the metering groove into the diluent chamber;
• a MEMS chip comprising a pump to pump diluted biological fluid from the diluent chamber and a sensor to measure a property of the diluted biological fluid;
• and
• an absorbent material enclosure in fluid communication with the pump, the absorbent material enclosure containing an absorbent material to absorb diluted biological fluid pumped from the diluent chamber;
• wherein the syringe body further comprises a vent port aligned with the biological fluid inlet to vent air from the metering groove, wherein the vent port vents air into the absorbent material enclosure.

A biological fluid dilution device, comprising:

• a syringe base portion comprising a piston tube at a rear end of the syringe base portion;
• a syringe end cap pressure fitted to a front end of the syringe base portion to form a diluent chamber, wherein the diluent chamber is partially filled with a diluent fluid;
• a moveable piston slidably engaged in the piston tube and forming a fluid-tight seal with an interior surface of the piston tube, wherein the moveable piston comprises a metering groove to contain a precise volume of a biological fluid between the metering groove and the interior surface of the piston tube;
• and
• a biological fluid inlet on the piston tube capable of delivering the biological fluid to the metering groove, wherein the moveable piston is slidable toward the diluent chamber to introduce the biological fluid in the metering groove into the diluent chamber, and wherein the syringe base portion and syringe end cap are formed of a polymer having a water vapor transmission rate of 0.5 g·mil/(24 hr·100 in2) or less.