Measuring volume and constituents of cells
A method for determining a mean cell volume for a blood sample includes: illuminating the sample with incident light at a plurality of illumination wavelengths and obtaining a two-dimensional image of the sample at each of the plurality of illumination wavelengths; identifying a plurality of cells that appear in each of the images; for each one of the plurality of cells, determining an integrated optical density corresponding to each of the plurality of illumination wavelengths; for each one of the plurality of cells, determining a cell volume based on the integrated optical densities corresponding to each of the plurality of illumination wavelengths; and determining the mean cell volume for the blood sample from the cell volumes for each one of the plurality of cells.
1. A method of determining a hemoglobin content value of a red blood cell, the method comprising:
illuminating the cell with light at multiple wavelengths;
for each one of the multiple wavelengths, determining a volume of the cell and an optical density of the cell from a cell image; and
determining the hemoglobin content value of the cell based on a combination of the volumes of the cell and the optical densities of the cell corresponding to the multiple wavelengths.
2. The method of claim 1 , wherein the combination of the volumes of the cell and the optical densities of the cell comprises a linear combination of the volumes of the cell and the optical densities of the cell.
3. The method of claim 2 , further comprising:
for each one of the multiple wavelengths, determining an area of the cell; and
determining the hemoglobin content value of the cell based on a combination of the volumes of the cell, the optical densities of the cell, and the areas of the cell corresponding to the multiple wavelengths.
4. The method of claim 3 , further comprising, for each one of the multiple wavelengths, determining the volume of the cell based on the area of the cell corresponding to the one wavelength.
5. The method of claim 1 , wherein the multiple wavelengths comprise at least three wavelengths.
6. The method of claim 1 , wherein the multiple wavelengths comprise at least four wavelengths.
7. The method of claim 1 , further comprising:
obtaining a set of cell images, wherein each image in the set corresponds to a different one of the multiple wavelengths; and
for each one of the multiple wavelengths, determining the volume of the cell and the optical density of the cell from a corresponding one image of the set of cell images.
8. The method of claim 1 , further comprising, for each one of the multiple wavelengths, determining the volume of the cell corresponding to the one wavelength based on a ratio of a mean optical density to a maximum optical density for the cell corresponding to the one wavelength.
9. The method of claim 1 , further comprising, for each one of the multiple wavelengths, determining the volume of the cell corresponding to the one wavelength based on a ratio of a mean optical density to a sum of a maximum optical density for the cell corresponding to the one wavelength and a wavelength-dependent correction factor.
10. The method of claim 2 , wherein the linear combination of the volumes of the cell and the optical densities of the cell comprises a set of weight coefficients, the method further comprising determining values of the set of weight coefficients from a reference set of samples.
11. The method of claim 1 , further comprising:
determining hemoglobin content values for a plurality of red blood cells; and
determining a mean cell hemoglobin value for a blood sample comprising the plurality of red blood cells based on the hemoglobin content values for the plurality of red blood cells.
12. The method of claim 11 , wherein the blood sample is a control composition, the method further comprising comparing a reference mean cell hemoglobin value for the control composition to the determined mean cell hemoglobin value for the control composition to assess an operating condition of a blood analysis device.
13. The method of claim 12 , further comprising performing a calibration of the blood analysis device if a difference between the reference mean cell hemoglobin value and the determined mean cell hemoglobin value for the control composition exceeds a threshold value.
14. The method of claim 13 , wherein performing the calibration comprises determining, from one or more reference samples, a plurality of weight coefficients that are used to determine the hemoglobin content value of the cell.
15. A system for determining a hemoglobin content value of a red blood cell, the system comprising:
an illumination source configured to illuminate the cell with light at multiple wavelengths;
a detector configured to obtain one or more images of the cell; and
an electronic processor configured to:
for each one of the multiple wavelengths, determine a volume of the cell and an optical density of the cell from the one or more images of the cell; and
determine the hemoglobin content value of the cell based on a combination of the volumes of the cell and the optical densities of the cell corresponding to the multiple wavelengths.
16. A method of determining a hemoglobin content value of a red blood cell, the method comprising:
applying one or more stains to the cell;
illuminating the cell with light at multiple wavelengths;
for each one of the multiple wavelengths, determining a volume of the cell and an optical density of the cell from a cell image; and
determining the hemoglobin content value of the cell based on a combination of the volumes of the cell and the optical densities of the cell corresponding to the multiple wavelengths.
17. The method of claim 16 , wherein the one or more stains comprise at least two stains.
18. The method of claim 17 , wherein the at least two stains comprise eosin and azure.
19. The method of claim 16 , wherein the one or more stains comprise at least three stains.
20. The method of claim 16 , wherein each of the one or more stains is associated with one of the multiple wavelengths.
21. The method of claim 16 , further comprising obtaining one or more images of the cell corresponding to the multiple wavelengths.
22. The method of claim 21 , wherein each one of the one or more stains is associated with one of the one or more images of the cell.
23. The method of claim 22 , wherein for each of the one or more stains, the associated one of the one or more images of the cell comprises information about absorption of light at one of the multiple wavelengths by the one stain.
24. The method of claim 16 , wherein the combination of the volumes of the cell and the optical densities of the cell comprises a linear combination of the volumes of the cell and the optical densities of the cell.
25. The method of claim 24 , further comprising:
for each one of the multiple wavelengths, determining an area of the cell; and
determining the hemoglobin content value of the cell based on a combination of the volumes of the cell, the optical densities of the cell, and the areas of the cell corresponding to the multiple wavelengths.
26. The method of claim 25 , further comprising, for each one of the multiple wavelengths, determining the volume of the cell based on the area of the cell corresponding to the one wavelength.