A critical analysis of some thyroid function tests.

The results of a comparative study of thyroid function tests are reported, the assay for PBI having been used for reference. The merits and sources of error of the Bio-Rad column test, Thyopac-4 test and T3-RIA test are discussed with reference to PBI. The correlation coefficients and the sources of error being taken into consideration, PBI represents a fairly reliable indicator of T4 values and recommends itself on these grounds as a basic routine procedure, the more so as it is simple, cheap and suited for automated analysis. In case of iodine contamination or of the necessity for a selective identification of the T4 factor, the T4 column test is equally reliable. The T3-RIA test will be valuable in special diagnostic problems.