Dynamic range extension systems and methods for particle analysis in blood samples

Inventors

Adams, Thomas H. • Wanders, Bart J. • Roche, John • Kasdan, Harvey L.

Assignees

Iris International Inc

Abstract

For analyzing a sample containing particles of at least two categories, such as a sample containing blood cells, a particle counter subject to a detection limit is coupled with an analyzer capable of discerning particle number ratios, such as a visual analyzer, and a processor. A first category of particles can be present beyond detection range limits while a second category of particles is present within respective detection range limits. The concentration of the second category of particles is determined by the particle counter. A ratio of counts of the first category to the second category is determined on the analyzer. The concentration of particles in the first category is calculated on the processor based on the ratio and the count or concentration of particles in the second category.

Core Innovation

The invention relates to a method for measuring a quantity of a first cell type in a blood fluid sample that includes a second cell type, where the first cell type is different from the second cell type. The method determines a population of the second cell type in a first volume of the sample by flowing the first volume through a hematology cell counter, and this second-cell population is used for a ratio-based calculation of the first-cell quantity measure.

The method acquires images of a first number of the first cell type and a second number of the second cell type. Images are acquired by injecting a second volume of the sample into a sheath fluid flowing within a flowcell to provide a sample stream having a thickness and a width greater than the thickness, with the images acquired along an image path traversing the thickness of the sample stream.

A ratio of the first number of the first cell type to the second number of the second cell type is determined from the acquired images, and a cell quantity measure of the first cell type in the sample is calculated using the ratio and the population of the second cell type. The approach combines hematology cell counter measurements with image-based ratio determination and uses a ribbon-shaped sample stream to extend effective dynamic range and correct miscounting behavior.

Claims Coverage

The independent claim covers a ratio-based hematology method with four inventive features: counter-determined second-cell population, sheath-fluid flowcell imaging along stream thickness path, image-derived ratio of first-to-second cell numbers, and calculated first-cell quantity measure using the ratio and second-cell population.

The claim coverage combines a hematology cell counter-based population determination for a second cell type with image acquisition in a sheath-fluid flowcell and an image-derived ratio, which is then used to calculate a cell quantity measure of a different first cell type.

Stated Advantages

Documented Applications