Abstract: The present invention provides a disposable ultra-filtration system comprising a disposable pipetting tip and a disposable ultra-filtration cartridge, wherein the cartridge includes a membrane filtration chamber and a dead-end channel. In use, a piston in the pipette pressurizes air within the channel; the pressurized air can subsequently move the piston and cause a reverse flow back through the membrane of the cartridge, unplugging the pores thereof. Also disclosed is an automated workstation incorporating the disposable ultra-filtration system, and a system comprising the automated workstation, useful for measuring the free therapeutic drug concentration and free hormone concentration in a sample.

Abstract: Some embodiments of the invention provide a system for measurement of at least two hemoglobin species in a patient's blood sample by spectroscopy, and measurement of at least pH of the blood sample by biosensor. The system comprises a disposable cartridge adapted for insertion into a slot of an analyzer, and the results are used to monitor the acid-base status of a patient. A method for monitoring the acid-base status of a patient using the system is also provided.

Abstract: The present invention provides a filtration assembly in the form of a disposable cartridge. A key feature of the invention is a filtration chamber having a porous membrane also referred to as a filter, a sample inlet to the filtration chamber, and an outlet for outflow of the fraction of sample that does not penetrate the membrane. The membrane can be used in any configuration, for example a hollow fiber. The fraction of sample that penetrates the membrane is referred to as the filtrate, and the fraction that does not penetrate the membrane is referred to as the retentate or concentrate. Some uses of the cartridge are to prepare plasma from blood, and to prepare a plasma ultra-filtrate from plasma, without the need for centrifugation. Many therapeutic drugs are highly protein bound, and a plasma ultra-filtrate is sometimes required to measure the unbound biologically active drugs.