US4978624A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reagent for the determination of a differential white blood cell count
Assignee: Bayer Corp
•
Filing: 1988-09-14
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Granted: 1990-12-18
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Expires: 2008-09-14
Abstract
Abstract This invention relates to a method for the rapid determination of a differential white blood cell count in a sample, which method comprises: (a) preparing a reagent solution comprising formaldehyde or paraformaldehyde; a surfactant; a sugar or sugar alcohol; and a buffer; and (b) rapidly mixing the reagent solution with the sample to be analyzed to form a reaction mixture, wherein both the reagent solution and the sample are initially at room temperature; and (c) rapidly heating the reaction mixture to a temperature of from about 62 DEG C. to about 72 DEG C. in order to lyse the red blood cells in the sample and fix the white blood cells in said sample. The invention also relates to the reagent solution of part (a) of the method.
Inventors
- 👤 John F. Cremins
- 👤 Young R. Kim
- 👤 Michael J. Malin
- 👤 Louis D. Sclafani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:36
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/5005; G01N33/5094; G01N1/00; G01N1/28; G01N1/30; G01N2001/305; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/101666; Y10T436/107497; Y10T436/108331
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
63 words
A composition for use as a reagent solution in the determination of a differential white blood cell count which comprises, in admixture, an aqueous solution of: (a) a surfactant; (b) formaldehyde in a concentration of from about 4.5% to about 6.6% weight/volume; (c) a sugar alcohol; and (d) a buffer to maintain the pH of said composition at between about 6.6 and 7.6.
Claim 2
Dependent Claim
63 words
A composition for use as a reagent solution in the determination of a differential white blood cell count which comprises, in admixture, an aqueous solution of: (a) a surfactant; (b) formaldehyde in a concentration of from about 4.5% to about 6.6% weight/volume; (c) a sugar alcohol; and (d) a buffer to maintain the pH of said composition at between about 6.6 and 7.6.
Claim 3
Dependent Claim
26 words
The composition of claim 1 wherein said surfactant comprises an alkali metal salt of an alkyl sulfate containing from about 10 to about 16 carbon atoms.
Claim 4
Dependent Claim
14 words
The composition of claim 2 wherein said surfactant comprises an alkali metal dodecyl sulfate.
Claim 5
Dependent Claim
12 words
The composition of claim 3 wherein said surfactant is sodium dodecyl sulfate.
Claim 6
Dependent Claim
17 words
The composition of claim 2 wherein said surfactant is present in an amount of about 0.36 mm.
Claim 7
Dependent Claim
20 words
The composition of claim 1 wherein formaldehyde is present in an amount of from about 5.3% to about 5.9% weight/volume.
Claim 8
Dependent Claim
19 words
The composition of claim 1 wherein said sugar alcohol is selected from the group consisting of sorbitol and mannitol.
Claim 9
Dependent Claim
11 words
The composition of claim 7 wherein said sugar alcohol is sorbitol.
Claim 10
Dependent Claim
22 words
The composition of claim 7 wherein said sugar alcohol is present in an amount of from about 9.0% to about 13.5% weight/volume.
Claim 11
Dependent Claim
22 words
The composition of claim 9 wherein said sugar alcohol is present in an amount of from about 11.0% to about 12.0% weight/volume.
Claim 12
Dependent Claim
13 words
The composition of claim 1 which further comprises an alkali metal chloride salt.
Claim 13
Dependent Claim
22 words
The composition of claim 11 wherein said alkali metal chloride salt is selected from the group consisting of NaCl, KCl and LiCl.
Claim 14
Dependent Claim
10 words
The composition of claim 12 wherein said salt is NaCl.
Claim 15
Dependent Claim
22 words
The composition of claim 12 wherein said salt is present in an amount of from about 68 mM to about 103 mM.
Claim 16
Dependent Claim
18 words
The composition of claim 1 wherein the pH of said composition is from about 6.9 to about 7.3.
Claim 17
Dependent Claim
22 words
The composition of claim 1 wherein said buffer comprises a mixture of Na 2 HPO 4 and NaH 2 PO 4 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |