Method and a system for determinations of cell suspensions

A method of determining a concentration of a substance in a cell suspension, said method comprising the following steps:

• using the results of absorption measurements performed at n local sample volumes contained at different average chamber heights of a chamber arrangement comprising the cell suspension, wherein a local substance concentration in said respective local sample volumes determined based on said respective absorption measurements;
• using a substance concentration model comprising local substance concentration as a function of chamber height, and
• determining the substance concentration as the infinite chamber height substance concentration using said substance concentration model and the determined local substance concentrations, wherein n is at least 2, such as at least 3, such as at least 4,
• wherein the determination of the substance concentration model comprising mapping the local substance concentrations (Lc-substance) of the local sample volumes as a function of the height Lc-substance(z) and calculating a best fitting curve to said mapping and extrapolating said best fitting curve to a height z→∞ and determining the substance concentration as the substance concentration at the height Z=∞.

A method of determining a concentration of a substance in a cell suspension, said method comprising the following steps:

• using the results of absorption measurements performed at n local sample volumes contained at different average chamber heights of a chamber arrangement comprising the cell suspension, wherein a local substance concentration in said respective local sample volumes determined based on said respective absorption measurements;
• using a substance concentration model comprising local substance concentration as a function of chamber height, and
• determining the substance concentration as the infinite chamber height substance concentration using said substance concentration model and the determined local substance concentrations,
• wherein n is at least 2, such as at least 3, such as at least 4;
• wherein the cell suspension is whole blood and the substance is Hb, said method further comprises determining the Mean Corpuscular Hemoglobin (MCH), said method comprising performing at least one absorption measurement at a low chamber heights of about 5 μm or less, and determining the from said absorption measurement at said low chamber height, wherein the low chamber height is from about 2 μto about 3.5 μm, such as from about 2.5 to about 3 μm, wherein the absorption measurement at said low chamber height comprises acquiring at least one image and identifying image areas of a plurality of individual red blood cells and determining the absorbance of said identified areas and correlating the determined absorbance to the MCH, preferably the method comprises counting the number of the plurality of individual red blood cells, determining the average absorbance of a blood cell and correlating the average absorbance of a blood cell to the MCH, preferably the plurality of individual red blood cells are identified as non-overlapping red blood cells.

A system for determining a concentration of a substance in a cell suspension, said system comprising a computer system programmed for causing the system to execute a method of determining a concentration of a substance in a cell suspension, said method comprising the following steps:

• using the results of absorption measurements performed at n local sample volumes contained at different average chamber heights of a chamber arrangement comprising the cell suspension, wherein a local substance concentration in said respective local sample volumes determined based on said respective absorption measurements;
• using a substance concentration model comprising local substance concentration as a function of chamber height, and
• determining the substance concentration as the infinite chamber height substance concentration using said substance concentration model and the determined local substance concentrations, wherein n is at least 2, such as at least 3, such as at least 4, wherein the system further comprises:
• a chamber arrangement comprising n different chamber heights configured for being loaded by said cell suspension by flowing, and being at least partially optically transparent for at least one preselected wavelength to at least partially allow a light beam of said preselected wavelength passing through the chamber arrangement at said chamber heights,
• a light source configured for emitting light comprising at least said preselected wavelength and being arranged to illuminate at least one a local sample volume at one of said n sample heights
• an image acquisition device configured for acquire images of light passing through said local sample volume wherein said computer system further is programmed for processing images obtained by said image acquisition device of local sample volumes at n different heights to determine the local substance concentration in each of said respective local sample volumes, wherein n is at least 2, such as at least 3, such as at least 4, such as 2-10.