Rapid radioimmunoassay of triiodothyronine.

The method used in this report is based on the immunological production of a specific antisera to tnlodothyronine (T3) in rabbits. Conducted at 4 #{176}C, the radioimmunoassay requires three to five days to complete. Hoping to speed this assay, we investigated the influence of time, temperature, and pH. Incubation at 37 #{176}C and pH 8.0 for 30 mm did not deleteriously affect either precision, specificity, reproducibility, or accuracy. Bound and unbound T3 were separated in 10 mm by adding polyethylene glycol (“Canbowax 6000”) at 0-4 #{176}C. T3 was prevented from binding to thyroxine-binding globulin by the addition of 8-anilino-1-naphthalene sulfonic acid. To minimize the differences in protein concentration between standards and unknowns, we added T3-free serum to all standards. Thus, a simplified and convenient method is described for measurement of T3 that is suitable for clinical use because it is simpler and faster than previously reported methods. Additional Keyphrases: assessment of thyroid function #{149} thyrotoxicosis #{149} hyperand hypothyroidism