Enzyme immunoassay of serum thyroxine with the "Autochemist" multichannel analyzer.

We have modified the homogeneous enzyme immunoassay of thyroxine and have adapted it to the AutoChemist. Both enzyme immunoassay and radioimmunnoassay procedures were performed on 2016 patients' sera on which thyroxine determinations had been ordered. We find the automated enzyme immunoassay to be precise and accurate, and for the first time it permits total automation of an immunoassay on a multichannel biochemical-profiling instrument. More importantly, it represents the first time that a thyroid-function test has been included in a multitest biochemical screening profile performed on a single automated instrument.