Method and system for determining plasma protein content of whole blood using refractometry
Inventors
Hlavinka, Dennis J. • Felt, Thomas J.
Assignees
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Publication Number
US-12605495-B2
Publication Date
2026-04-21
Expiration Date
Abstract
A method and system is provided that measures plasma protein levels of whole blood while a plasma donor is connected to an apheresis machine. A refractometer associated with the apheresis machine is capable of receiving a portion of a disposable tubing set including an integrated cuvette and prism. The integrated cuvette of the disposable tubing set can be inserted into a receiving space of the refractometer associated with the apheresis machine such that the light source and the sensor are oriented relative to the prism and a sensing surface of the integrated cuvette in a precise alignment. Calibration of the refractometer is made using anticoagulant pumped through the disposable tubing set including the integrated cuvette and prism. Based on a light intensity associated with this calibration, whole blood is then measured to determine plasma protein levels and donor eligibility.
Core Innovation
The patent describes determining component content of a fluid sample using a refractometer that includes a light source and a light sensor. The refractometer is calibrated by identifying a calibration pixel pattern of first pixels of the light sensor illuminated by light that has reflected off a sensing surface of a container including a reference fluid having a known reference density, and a sample pixel pattern of second pixels is then identified when the fluid sample is present.
A pixel shift distance along the light sensor is determined between the calibration pixel pattern and the sample pixel pattern, measured between first pixels and second pixels having a common brightness. The component content is determined based on the pixel shift distance multiplied by K, where K is an experimentally derived proportionality constant specific to at least one of prism material of the refractometer, wavelength of the light source, resolution of the light sensor, and an optical geometry of the refractometer, and the product is added to C, where C is a simulated plasma protein concentration value of the reference fluid.
The patent further describes a prism-based container and a system architecture that supports measuring while controlling how the sensing surface interacts with red blood cells. Red blood cells are addressed by positioning with gravity so that light sensor/prism arrangement causes red blood cells to move away from the sensing surface, and by optionally pausing fluid flow through the container while identifying the sample pixel pattern.
In an apheresis system, the controller activates the apheresis machine to separate a fluid component from the fluid sample when the determined component content is within a predetermined range. The system claim also includes a support member configured to hold the container relative to the light source and the light sensor such that light generated by the light source reflects off the sensing surface to the light sensor.
Claims Coverage
The independent claims are clm-00001, clm-00010, and clm-00015. Across these claims, the inventive core is based on comparing calibration and sample pixel patterns to determine a pixel shift distance, and then computing component content from the pixel shift using K multiplied by the pixel shift distance and added to C, where K depends on prism material and optical or measurement parameters and C is a simulated plasma protein concentration value of the reference fluid. Additional inventive features relate to prism-containing container support, pixel-pattern shift identification with common brightness, and integration with an apheresis machine conditioned on a predetermined component-content range.
Pixel-pattern calibration and pixel-shift component determination using K and C
Calibrating the refractometer by identifying a calibration pixel pattern of first pixels of the light sensor illuminated by light from the light source that has reflected off a sensing surface of a container including a reference fluid having a known reference density; identifying a sample pixel pattern of second pixels of the light sensor illuminated by light from the light source that has reflected off the sensing surface when the fluid sample is present in the container; identifying a pixel shift distance along the light sensor from the calibration pixel pattern to the sample pixel pattern, the pixel shift distance measured between the first pixels and the second pixels having a common brightness; and determining the component content of the fluid sample based on the pixel shift distance multiplied by K, the product of which is added to C, where K is an experimentally derived proportionality constant specific to at least one of prism material of the refractometer, wavelength of the light source, resolution of the light sensor, and an optical geometry of the refractometer, and C is a simulated plasma protein concentration value of the reference fluid.
Prism-based system support for calibration and sample pixel-pattern identification
A system for measuring component content comprising a light source, a light sensor, a container including a prism having a sensing surface, and a support member configured to hold the container relative to the light source and the light sensor such that light generated by the light source reflects off the sensing surface to the light sensor; and a controller configured to calibrate by identifying a calibration pixel pattern of first pixels illuminated by reflected light when a reference fluid is present having a known reference density, identify a sample pixel pattern when the fluid sample is present, identify a pixel shift distance along the light sensor from the calibration pixel pattern to the sample pixel pattern having a common brightness, and determine the component content based on the pixel shift distance multiplied by K and added to C, with K experimentally derived and specific to at least one of prism material of the prism, wavelength of the light source, resolution of the light sensor, and an optical geometry of the prism, and C being a simulated plasma protein concentration value of the reference fluid.
Apheresis system refractometer measurement linked to activation based on predetermined range
An apheresis system comprising an apheresis machine configured to separate a fluid component from a fluid sample, and a refractometer configured to measure component content of the fluid sample including a light source, a light sensor, a cuvette including a prism with a sensing surface, and a support member configured to hold the cuvette relative to the light source and the light sensor such that light generated by the light source reflects off the sensing surface to the light sensor; and a controller configured to calibrate by identifying a calibration pixel pattern illuminated by reflected light while a reference fluid is present, identify a sample pixel pattern illuminated by reflected light while the fluid sample is present, identify a pixel shift distance having common brightness, determine component content based on pixel shift distance multiplied by K and added to C, and activate the apheresis machine to separate the fluid component when the component content determined is within a predetermined range, where K is experimentally derived and specific to at least one of prism material of the refractometer, wavelength of the light source, resolution of the light sensor, and optical geometry of the refractometer, and C is a simulated plasma protein concentration value of the reference fluid.
Across clm-00001, clm-00010, and clm-00015, the claims center on calibration and measurement using calibration and sample pixel patterns, extracting a pixel shift distance with common brightness, and determining component content from that pixel shift scaled by an experimentally derived constant K and offset by C, where C is a simulated plasma protein concentration value. The system claim adds prism-based sensing surface support relative to the light source and light sensor, and the apheresis claim integrates the component-content determination with activation of an apheresis machine within a predetermined range.
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