Claims
- 1. A method for determining the concentration of the free fraction of triiodothyronine present in a biological fluid containing natural binders, with said free fraction and the bound fraction of triiodothyronine being in equilibrium, comprising the steps of:
- (a) contacting a sample of said biological fluid with an unlabeled antibody to produce a reacted unlabeled antibody, with the quantity of said unlabeled antibody and the affinity of said unlabeled antibody for said free fraction of said triiodothyronine selected such that said unlabeled antibody does not substantially affect said equilibrium between said free fraction and said bound fraction of said triiodothyronine;
- (b) separating said sample from said reacted unlabeled antibody of step (a);
- (c) incubating said reacted unlabeled antibody of step (b) with a labeled tracer substance for cross-reaction with said unlabeled antibody, with the affinity of said tracer for said unlabeled antibody being substantially higher than or substantially lower than the affinity of said labeled antibody for said free fraction of said triiodothyronine, said tracer having a molecular structure which differs from that of the triiodothyronine to be determined and which structural difference has not been brought about by the labeling; and,
- (d) measuring the amount of said tracer which is or is not bound to said unlabeled antibody and calculating from said tracer amount the concentration of said free fraction of said triiodothyronine.
- 2. The method of claim 1 wherein said affinity of said tracer for said unlabeled antibody is substantially higher than said affinity of said unlabeled antibody for said free fraction of triiodothyronine.
- 3. The method of claim 1 wherein said affinity of said tracer for said unlabeled antibody is substantially lower than said affinity of said unlabeled antibody for said free fraction of triiodothyronine.
- 4. The method of claim 1, wherein said unlabeled antibody is a polyclonal or monoclonal antibody.
- 5. The method of claim 1, wherein said tracer is labeled with an entity selected from the group consisting of radioactive atom, a fluorescing group, a chemiluminescent group, an enzyme, and a photochromophor.
- 6. The method of claim 5 wherein said method is used for determining the free fraction of triiodothyronine, and wherein said tracer is a triiodothyronine which has been modified at the amino group, at the carboxyl group or at another site in the molecule.
- 7. The method of claim 5 wherein said tracer is labeled with iodine 125.
- 8. The method of claim 1 wherein the tracer is selected from the group consisting of 3,3',5,5'-tetraiodothyroacetic acid; 3,5-diiodo-4-(3,5-diiodo-4-oxyphenyl)-benzenesulfonic acid; N-(methylphosphinoacetyl)-3,3',5,5'-tetraiodothyrosine; and N-(.xi.-aminocaprol)-3,3',5,5'-tetraiodothyrosine.
Priority Claims (1)
Number |
Date |
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Kind |
36 26 468 |
Aug 1986 |
DEX |
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Parent Case Info
This is a divisional of application Ser. No. 07/884,874 filed on May 18, 1992, now U.S. Pat. No. 5,714,336, which is a continuation application of Ser. No. 07/697,494 filed on May 3, 1991, abandoned, which is a continuation application of Ser. No. 07/488,503 filed on Mar. 5, 1990, abandoned, which is a continuation application of Ser. No. 07/081,185 as filed on Aug. 4, 1987 abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (8)
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0106615 |
Apr 1984 |
EPX |
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Divisions (1)
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Number |
Date |
Country |
Parent |
884874 |
May 1992 |
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Continuations (3)
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Number |
Date |
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Parent |
697494 |
May 1991 |
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Parent |
488503 |
Mar 1990 |
|
Parent |
081185 |
Aug 1987 |
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