Radioimmunological method of determining the thyroid function by an in vitro test in blood serum

摘要

The present invention provides an improved method for determining the thyroid function by means of an in vitro test using blood serum. Such a method involves an improvement of the procedure whereby (a) a patient's blood serum sample is mixed with a solution containing radioactive thyroxine and with a compound that liberates thyroxine from thyroxine- binding globulin; (b) the test mixture is buffered to achieve proper conditions for carrying out a thyroxine-binding immunoreaction; (c) an antiserum is added to provide antibodies which bind a portion of the thyroxine present by means of such a thyroxine-binding immunoreaction; (d) unbound thyroxine is thereafter separated from the antibody-bound thyroxine; and (e) the relative quantities of bound and unbound thyroxine are then determined by measurement of radioactivity. P PIn accordance with the present invention, such a procedure is improved by adding to the test mixture, after it has been appropriately buffered, a second additional sample of the patient's blood serum. This second sample of the patient's serum acts as a "correcting" or "normalizing" second binding agent, the addition of which improves the accuracy of thyroid function determination by means of the radioimmunoassay procedure.