US3988431A
Expired / Lapsed
US
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Radioassay of folates
Assignee: Becton Dickinson and Co
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Filing: 1974-12-12
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Granted: 1976-10-26
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Expires: 1994-12-12
Abstract
Abstract In the radioassay of folates, the standard is prepared by using folic acid (pteroyl glutamic acid; PGA) as the standard folate at a pH of 9.2 to 9.4. At such pH values, folic acid and 5-methyltetrahydrofolic acid (the predominant folate in human serum) have essentially identical reactivity towards folate binders, whereby folic acid can replace unstable 5-methyltetrahydrofolic acid standard for such assays.
Inventors
- 👤 Joan K. Givas
- 👤 Sidney Gutcho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:44
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/82
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
43 words
In a process for preparing a standard for the radioassay of folate by incubation of radiolabeled folate, standard folate and folate binder, the improvement comprising: employing folic acid as the standard and effecting the incubation at a pH of from 9.2 to 9.4.
Claim 2
Dependent Claim
43 words
In a process for preparing a standard for the radioassay of folate by incubation of radiolabeled folate, standard folate and folate binder, the improvement comprising: employing folic acid as the standard and effecting the incubation at a pH of from 9.2 to 9.4.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the radiolabeled folate is radiolabeled folic acid.
Claim 4
Dependent Claim
14 words
The process of claim 2 wherein the radiolabeled folic acid is tritiated folic acid.
Claim 5
Dependent Claim
14 words
The process of claim 2 wherein the radiolabeled folic acid is radioiodinated folic acid.
Claim 6
Dependent Claim
113 words
In a process for the radioassay of folate, the improvement comprising: incubating a plurality of standard samples, each sample containing a fixed concentration of folate binder, a fixed concentration of radiolabeled folate and a different known concentration of folic acid as a standard folate, said incubating being effected at a pH of from 9.2 to 9.4; preparing a standard curve from said standard samples; incubating a serum sample containing an unknown concentration of folate, said fixed concentration of folate binder and said fixed concentration of said radiolabeled folate incubation being effected at a pH of from 9.2 to 9.4; and determining the amount of folate in said serum sample from said standard curve.
Claim 7
Dependent Claim
113 words
In a process for the radioassay of folate, the improvement comprising: incubating a plurality of standard samples, each sample containing a fixed concentration of folate binder, a fixed concentration of radiolabeled folate and a different known concentration of folic acid as a standard folate, said incubating being effected at a pH of from 9.2 to 9.4; preparing a standard curve from said standard samples; incubating a serum sample containing an unknown concentration of folate, said fixed concentration of folate binder and said fixed concentration of said radiolabeled folate incubation being effected at a pH of from 9.2 to 9.4; and determining the amount of folate in said serum sample from said standard curve.
Claim 8
Dependent Claim
13 words
The process of claim 5 wherein the radiolabeled folate is radiolabeled folic acid.
Claim 9
Dependent Claim
14 words
The process of claim 6 wherein the radiolabeled folic acid is tritiated folic acid.
Claim 10
Dependent Claim
14 words
The process of claim 5 wherein the radiolabeled folic acid is radioiodinated folic acid.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |