Rapid radioimmunoassay for the evaluation of thyroxine in unextracted serum
| Autor: | J. Herrmann, H.L. Krüskemper, H. J. Rusche |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Time Factors
Clinical Biochemistry Radioimmunoassay Cross Reactions Biochemistry Anilino Naphthalenesulfonates Iodine Radioisotopes Thyroxine-binding globulin Blood serum Methods Animals Humans Displacement (orthopedic surgery) High concentration Autoanalysis Chromatography biology Chemistry Microchemistry Biochemistry (medical) Dextrans Blood Proteins General Medicine Blood proteins Dilution Standard curve Thyroxine Evaluation Studies as Topic Charcoal biology.protein Indicators and Reagents Rabbits Protein Binding |
| Zdroj: | Clinica Chimica Acta. 54:69-79 |
| ISSN: | 0009-8981 |
| DOI: | 10.1016/0009-8981(74)90044-8 |
| Popis: | A rapid, specific, precise and sensitive radioimmunoassay (RIA) for measurements of thyroxine (T4) in unextracted serum is presented. The assay is characterized by the use of specific thyroxine binding rabbit antiserum in a final dilution of 1: 2000 and 8-anilinonaphthalene 1-sulphonic acid (ANS, 600 μg per test-tube) for the displacement of T4 from its binding with thyroxine binding globulin. The method described has several advantages over conventional displacement techniques. The setting up of the assay is half automatic, the working time is short (about 4 h for 100 samples), only 25 μl of serum are needed for one sample, the displacement of thyroxine from serum protein by ANS is almost complete (98%), the sensitivity of the assay (0.24 μg T4/dl) is far greater than that of displacement methods, the standard curve is linear from 0.24–60 μg T4/dl, thereby allowing accurate measurements over a wide range in one attempt. The overall agreement between the results obtained using the RIA and a displacement technique in 189 sera of different thyroxine concentrations was good (r = 0.9407). In sera of hyperthyroid patients, however, the average T4 estimate by radioimmunoassay exceeded those obtained using the displacement method. In recovery experiments with 4 methods for the evaluation of T4, good agreement between expected and measured values, even in the high concentration range, was seen with the radioimmunoassay as well as with the FBI determination, whereas poor agreement was found with two displacement techniques. The reason for this was found in the levelling off of the standard curves of the conventionally processed displacement methods when the thyroxine concentration exceeds 17 μg/dl. Good recovery of added thyroxine even in the high concentration range was achieved when the procedure of the displacement method was appropriately adjusted. Therefore, the discrepancies observed between the results when obtained from radioimmunoassay or displacement techniques seem to depend on the methodological problems of a nonadjusted displacement method. |
| Databáze: | OpenAIRE |
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