Patent US5250438A successfully refreshed from Google Patents.
US5250438A
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US
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Method for differential determination of white blood cells using diazolidinyl urea to stabilize white blood cells
Assignee: Streck Inc
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Filing: 1990-05-09
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Granted: 1993-10-05
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Expires: 2010-05-09
Abstract
Abstract A new method for separation of white cells in differential hematology instruments is described. In the method described, white cell shrinkage is controlled by the use of diazolidinyl urea and accelerated with alcohol thereby providing a reproducible method for easy manipulation of the white cells. In addition, it was found that adsorption of blood platelets and red blood cells in the instruments can be prevented by use of a surfactant such as the polyols.
Inventors
- 👤 Wayne L. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:56
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/5005; G01N33/5094; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/101666; Y10T436/107497; Y10T436/108331
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
83 words
In a method for the differentiation of white blood cells in whole blood using a differential hematology analyzing instrument wherein a whole blood sample diluted with a diluent containing a white blood cell stabilizer is mixed with a lysing agent to lyse the red blood cells and differentiate said white blood cells for counting by said instrument, the improvement comprising using as said white blood stabilizer diazolidinyl urea in an amount sufficient to stabilize said white blood cells against shrinkage during said lysis.
Claim 2
Dependent Claim
83 words
In a method for the differentiation of white blood cells in whole blood using a differential hematology analyzing instrument wherein a whole blood sample diluted with a diluent containing a white blood cell stabilizer is mixed with a lysing agent to lyse the red blood cells and differentiate said white blood cells for counting by said instrument, the improvement comprising using as said white blood stabilizer diazolidinyl urea in an amount sufficient to stabilize said white blood cells against shrinkage during said lysis.
Claim 3
Dependent Claim
35 words
The improvement according to claim 1 wherein said diluent agent includes a surfactant glycol in an amount sufficient to reduce adsorption of blood platelets and red blood cells on surfaces of said hematology analyzing instruments.
Claim 4
Dependent Claim
55 words
The improvement according to claim 2 wherein the surfactant is a water-soluble polyalkylene ether glycol having the structure: Z(OR').sub.n OH wherein Z is H, alkyl, aryl or alkylaryl; R' is a divalent alkyl of 2 to 3 carbon atoms; n is greater or equal to 4; and block copolymers of ethylene oxide and propylene oxide.
Claim 5
Dependent Claim
17 words
The improvement according to claim 1 wherein the lysing reagent comprises one or more quaternary ammonium salts.
Claim 6
Dependent Claim
20 words
The improvement of claim 4 wherein the lysing agent is a mixture of dodecyltrimethyl ammonium chloride and tetradecyltrimethyl ammonium bromide.
Claim 7
Dependent Claim
26 words
The improvement of claim 4 wherein the lysing reagent includes a lower alkanol in an amount that accelerates the shrinking effect of said quaternary ammonium salt.
Claim 8
Dependent Claim
12 words
The improvement of claim 6 wherein the lower alkanol is isopropyl alcohol.
References Cited (Backward Citations)
US4185964A
Cited
US4286963A
Cited
US4303408A
Cited
US4346018A
Cited
US4528274A
Cited
US4637986A
Cited
US4745071A
Cited
US4882284A
Cited
US5039487A
Cited
US5008202A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |