Methods and compositions related to determination and use of white blood cell counts
Described herein is an analyte detection device and method related to a portable instrument suitable for point-of-care analyses. In some embodiments, a portable instrument may include a disposable cartridge, an optical detector, a sample collection device and/or sample reservoir, reagent delivery systems, fluid delivery systems, one or more channels, and/or waste reservoirs. Use of a portable instrument may reduce the hazard to an operator by reducing an operator's contact with a sample for analysis. The device is capable of obtaining diagnostic information using cellular- and/or particle-based analyses and may be used in conjunction with membrane- and/or particle-based analysis cartridges. Analytes, including proteins and cells and/or microbes may be detected using the membrane and/or particle based analysis system.
1. A cartridge for differential assay of white blood cell populations, the cartridge comprising:
a chamber;
a pad connected to the chamber via a fluid channel, wherein the pad is a reagent pad containing therein three binding agents each labeled with a different fluorophore;
a microsieve positioned at least partially within the chamber, wherein pores of the microsieve are configured to retain white blood cells from a blood sample and to allow red blood cells to pass through the microsieve,
wherein the fluorophore-labeled binding agents are flowed from the pad and over the microsieve and allowed to differentially bind to populations of white blood cells previously captured on the microsieve,
wherein an image can be obtained from the microsieve, and
wherein the fluorophore-labeled binding agents specifically bind to different populations of white blood cells so as to allow the different populations of cells to be distinguishably detectable by fluorescence.
2. The cartridge of claim 1 , wherein a first one of the binding agents binds CD2+ white blood cells, a second one of the binding agents binds CD4+ white blood cells, and a third one of the binding agents binds CD19+ white blood cells.
3. The cartridge of claim 1 , wherein at least one of the binding agents is an antibody to a white blood cell surface receptor.
4. The cartridge of claim 3 , wherein the antibody binds a surface receptor selected from the group consisting of CD2, CD4, CD19, and CD56.
5. The cartridge of claim 1 , wherein the microsieve is a polycarbonate track-etched microsieve.
6. The cartridge of claim 1 , wherein the volume of the blood sample is a known volume.
7. The cartridge of claim 1 , further comprising a support structure positioned beneath the microsieve and at least partially within the chamber, wherein the support structure maintains the microsieve in a relatively planar orientation and allows filtered material to pass through the microsieve.