Control material and methods for cell analyzers
This disclosure relates to verifying the operation of cell analyzers, including microscope-based cell imaging and counting analyzers. In one general aspect, a mixture of micro-beads having known characteristics is introduced into the analyzer. One or more images of the mixture are acquired with the analyzer's microscope, the images are analyzed, and a determination is made about whether results meet one or more predetermined quality control thresholds. Also disclosed is a hematology control material that can be used to perform the verification and includes a solvent, a dye dissolved in the solvent, and micro-beads suspended in the solvent. In another general aspect, a quality control method for the analyzers includes capturing images of samples that include patient cells using at least a microscope, extracting sample-specific information about properties of the patient samples from the images, and testing information from the samples against predetermined standards to verify the operation of the analyzer.
1. A method of verifying the operation of a cell analyzer having an automated microscope and image processing software for counting and analyzing cells and platelets in blood and which utilizes a test cartridge having a diluent/and or stain, the method comprising:
a) introducing into the test cartridge a mixture of 1) a plurality of a first type of micro-beads in a known amount of solution having a first known characteristic and a concentration that simulates a concentration of a first type of cells in blood and 2) a plurality of a second type of micro-beads in a known amount of solution having a second known characteristic and concentration that simulates a concentration of a second type of cells in blood;
b) interfacing the test cartridge with the cell analyzer;
c) separating a known amount of the mixture of micro-beads from the remaining amount of the mixture of micro-beads in the test cartridge;
d) mixing the known amount of the mixture of micro-beads in the test cartridge with an amount of diluent and/or stain that is sufficient to form a substantially uniform mixture of micro-beads and diluent and/or stain, wherein the micro-beads are suspended therein;
e) transferring the entire mixture into the imaging chamber that is defined in the body of the test cartridge;
f) allowing the particles in the mixture to settle to a bottom of the imaging chamber;
g) capturing one or more digital images of the settled particles in the imaging chamber that are selected to be statistically representative of the number and distribution of the first and second types of micro-beads;
h) counting all of at least one type of micro-beads in the images using imaging processing software;
i) obtaining a number of micro beads per unit volume of at least the one type of micro-beads in the mixture; and
j) comparing the number of micro-beads per unit volume of the one type of beads in the imaging chamber with the concentration of the one type of beads in solution.
2. The method of claim 1 wherein the mixture of beads is counted by image processing logic associated with the analyzer.
3. The method of claim 1 wherein the two types of micro-beads are counted separately by image processing logic associated with the analyzer according to their different characteristics.
4. The method of claim 1 wherein one type of micro-bead is a fluorescent micro-bead.
5. The method of claim 1 wherein the providing provides a mixture of micro-beads of different sizes.