Abstract: The present invention provides methods and apparatuses related to measurement of analytes, including measurements of analytes in samples withdrawn from a patient.

Abstract: The use of an optical or other measurement in a blood access system enables the determination of a fluid sample appropriate for measurement on a real time basis. This information can be used to control the blood access system and related measurement processes. The determination can be based on, for example, at least one of: optical density, optical scatter, analyte level, temperature, the absolute level of any of the preceding, the stability of any of the preceding, the rate of change of any of the preceding, or the value of any of the preceding relative to another determination. The determination can be made using, for example, at least one of: electrochemical sensor, ion specific electrode, capacitance measurement, impedance measurement, inductance measurement, conductivity measurement, optical measurement, and ultrasound measurement.

Abstract: Embodiments of the present invention provide robust systems for the removal and subsequent infusion of blood for measurement purposes, and embodiments of the present invention provide methods of operating such systems and providing capabilities such as predicting and avoiding occlusions and/or bubbles, managing occlusions and/or bubbles if they occur, automatic cleaning of the blood access system, and determining and managing the patency of the blood access site. Such operational challenges can occur during any of several phases of operation of a blood access system. Embodiments of the present invention can effectively incorporate a variety of inputs for the identification of trends consistent with present or pending occlusions. An embodiment of the present invention can be aware of the stage of operation, e.g., withdrawal, infusion, or cleaning, and the prior performance of the system.

Abstract: Events of interest are detected within a gamma ray detection system. Characteristics of undesired signals, including a multiplicity of events within the signal, a density of events within the signal, and other aspects are determined. The signal is filtered based on its expected characteristics. A signal which does not have the expected characteristics is rejected, and an image is formed that excludes those rejected signals.

Abstract: Events of interest are detected within a gamma ray detection system. Characteristics of undesired signals, including a multiplicity of events within the signal, a density of events within the signal, and other aspects are determined. The signal is filtered based on its expected characteristics. A signal which does not have the expected characteristics is rejected, and an image is formed that excludes those rejected signals.