Provided herein are red blood cell control compositions comprising one or more populations of lysable hydrogel particles having an impedance that is substantially similar to the impedance of a human red blood cell of average diameter; and a population of hemoglobin molecules or a population of dye molecules that have substantially similar absorbance as hemoglobin; wherein (i) and/or (ii) are present in an amount that corresponds to a normal blood sample or disease state, or (i) and (ii) are present at a ratio that corresponds to a normal blood sample or disease state.

Embodiments of the microfluidic device may include of an array of microfluidic cell capture chambers, each functionalized with a different antibody to recognize a target antigen, and a network of code-multiplexed Coulter counters placed at strategic nodes across the device to quantify the fraction of cell population captured in each microfluidic chamber. For example, an apparatus may comprise a fluid inlet port divided into a plurality of separate microfluidic paths, each separate microfluidic path configured to transport a plurality of cells, the plurality of separate microfluidic paths, each comprising a plurality of microfluidic cell capture chambers, an outlet port to discharge a merged output of cells from the plurality of microfluidic cell capture chambers, and a plurality of sensors to detect cells passing into or out of a microfluidic cell capture chamber.

Methods and systems for detecting and reporting subpopulations of neutrophils may involve using a nonce parameter to elucidate one or more other cell population parameters. Methods and systems for detecting and reporting subpopulations of neutrophils may involve structuring reports to elucidate one or more cell population parameters, particularly, but not exclusively, where the report of a cell population parameter might otherwise be ambiguous or a higher than usual likelihood of confusion.

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.

Particles such as blood cells can be categorized and counted by a digital image processor. A digital microscope camera can be directed into a flowcell defining a symmetrically narrowing flowpath in which the sample stream flows in a ribbon flattened by flow and viscosity parameters between layers of sheath fluid. A contrast pattern for autofocusing is provided on the flowcell, for example at an edge of a rear illumination opening. The image processor assesses focus accuracy from pixel data contrast. A positioning motor moves the microscope and/or flowcell along the optical axis for autofocusing on the contrast pattern target. The processor then displaces microscope and flowcell by a known distance between the contrast pattern and the sample stream, thus focusing on the sample stream. Blood cell images are collected from that position until autofocus is reinitiated, periodically, by input signal, or when detecting temperature changes or focus inaccuracy in the image data.

Particles such as blood cells can be categorized and counted by a digital image processor. A digital microscope camera can be directed into a flowcell defining a symmetrically narrowing flowpath in which the sample stream flows in a ribbon flattened by flow and viscosity parameters between layers of sheath fluid. A contrast pattern for autofocusing is provided on the flowcell, for example at an edge of a rear illumination opening. The image processor assesses focus accuracy from pixel data contrast. A positioning motor moves the microscope and/or flowcell along the optical axis for autofocusing on the contrast pattern target. The processor then displaces microscope and flowcell by a known distance between the contrast pattern and the sample stream, thus focusing on the sample stream. Blood cell images are collected from that position until autofocus is reinitiated, periodically, by input signal, or when detecting temperature changes or focus inaccuracy in the image data.

A microfluidic device for particle analysis, such as immunophenotyping, includes a plurality of microfluidic channels for the passage of a particle-laden fluid flow, a plurality of dedicated impedance sensors for generating impedance signals relative to each microfluidic sensor. The impedance sensors are CODES Coulter sensors, each having a distinct coded sequence for generating mutually orthogonal signals. The system uses a multi-frequency excitation signal for driving the Coulter sensors, such that the Coulter sensors generate multi-frequency impedance signals. The system outputs the multi-frequency signals of the plurality of impedance sensors as a single multi-frequency multiplexed signal, which is subsequently separated into a plurality of single-frequency multiplexed signals, which are then demodulated into single-frequency component signals corresponding to each of the Coulter sensors.