Green concentrated reagent for hematology systems

1. An aqueous concentrated reagent composition for use in a hematology analyzer, the concentrated reagent composition comprising a hemoglobin ligand, at least one metal sulfate, at least one phosphate-based buffer, and at least one antimicrobial agent, wherein the concentrated reagent composition is diluted by a dilution factor of between 10 and 20 to provide a working concentration reagent composition, and the aqueous concentrated reagent composition remains stable when stored at a temperature of about 2° C. to 30° C. for at least one year after date of manufacture.

2. The aqueous concentrated reagent composition of claim 1 , wherein the composition comprises or produces less than about 2 parts per million (ppm) of formaldehyde over a period of time of at least 1 year when stored at ambient temperature.

3. The aqueous concentrated reagent composition of claim 1 , further comprising a chelating agent.

4. The aqueous concentrated reagent composition of claim 3 , the composition comprising 10 to 100 g/L a chelating agent, wherein the chelating agent is tetrasodium EDTA; 10 to 50 g/L a hemoglobin ligand, wherein the hemoglobin ligand is imidazole; 20 to 100 g/L of a first metal sulfate, wherein the first metal sulfate is sodium sulfate; 15 to 60 g/L of a second metal sulfate, wherein the second metal sulfate is potassium sulfate; 10 to 80 g/L of a phosphate-based buffer, wherein the phosphate-based buffer is sodium phosphate monobasic;

and an antimicrobial agent selected from the group consisting of 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MIT), 5-bromo-5-nitro-1,3-dioxane, and 5-fluorouracil.

5. The aqueous concentrated reagent composition of claim 4 , the composition further comprising 60 to 300 g/L sodium potassium tartrate.

6. A method for analyzing a body fluid comprising: a) diluting the concentrated reagent composition of claim 3 from 10-fold to 20-fold to form the working concentration reagent composition; and b) mixing a body fluid with the working concentration reagent composition to form a diluted body fluid sample.

7. The method of claim 6 , wherein the body fluid is a blood sample containing blood cells, and the diluted body fluid sample is a diluted blood sample, wherein the chelating agent and the hemoglobin ligand are in an amount effective to provide reproducible hemoglobin and cell volume measurements over a temperature range from 15° C. to 32° C.; and

wherein the method further comprises c) analyzing said diluted blood sample to determine at least one physical parameter of said blood cells.

8. The method of claim 7 , wherein said blood cells comprise red blood cells and/or white blood cells.

9. The method of claim 7 , wherein said analyzing said diluted blood sample to determine at least one physical parameter comprises analyzing to determine mean cell volume of said blood cells.

10. The method of claim 7 , which further comprises mixing a lytic reagent with said diluted blood sample to lyse red blood cells prior to said analyzing said diluted blood sample.

11. The method of claim 7 , wherein said analyzing of said diluted blood sample to determine at least one physical parameter of said blood cells comprises an automated differential analysis of white blood cells to determine at least three subpopulations of white blood cells.

12. The method of claim 7 , wherein said analyzing said diluted blood sample to determine at least one physical parameter of said blood cells comprises analyzing to determine a number of platelets or analyzing to determine hemoglobin content.

13. The aqueous concentrated reagent composition of claim 1 , wherein the hemoglobin ligand is selected from the group consisting of imidazole, phenylimidazole, methylimidazole, ethylimidazole and butylimidazole.

14. The aqueous concentrated reagent composition of claim 1 , wherein the at least one metal sulfate is selected from the group consisting of sodium sulfate, potassium sulfate, potassium hydrogen sulfate, and sodium hydrogen sulfate.

15. The aqueous concentrated reagent composition of claim 14 , wherein the aqueous concentrated reagent composition comprises sodium sulfate and potassium sulfate and a weight ratio of sodium sulfate to potassium sulfate is from 0.5:1 to 3:1.

16. The aqueous concentrated reagent composition of claim 14 , wherein the working concentration reagent composition comprises from 25 to 75 mmol total sulfate anion.

17. The aqueous concentrated reagent composition of claim 1 , wherein the at least one phosphate-based buffer is selected from one or more of, potassium hydrogen phosphate, sodium hydrogen phosphate, sodium phosphate monobasic, or a hydrate thereof.

18. The aqueous concentrated reagent composition of claim 1 , wherein the composition comprises one or more antimicrobial agents selected from the group consisting of 5-fluorouracil, 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MIT), 5-bromo-5-nitro-1,3-dioxane, polyaminopropyl biguanide, 1,2-benzisothiazolin-3-one (BIT), 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 2-n-octyl-4-isothiazolin-3-one (OTT), ortho-phthaldialdehyde (OPA), and 1,2 dibromo-2,4 dicyanobutane (Bromothalonil).

19. The aqueous concentrated reagent composition of claim 1 , wherein the composition comprises one or more of the group consisting of an alkaline metal chloride, a platelet stabilizing agent, and an osmotic stabilizing agent.

20. The aqueous concentrated reagent composition of claim 1 , wherein upon aqueous dilution selected from at least 10-fold to 20-fold to form the working concentration reagent composition, the working concentration reagent composition exhibits each of: i) pH of 6.90 to 7.30 at ambient temperature; ii) conductivity of 19.05 to 20.00 mS/cm at ambient temperature; and iii) osmolality of 315 to 360 mOsm/Kg at ambient temperature.