In 31 severely ill patients of our intensive care unit an increased thyroid hormone
binding inhibition detected by quantitative measurement of the effect of ether extracts
of patients' sera on thyroxine tracer binding to TBG was found. As free fatty acids
in serum were diminished in these patients, their postulated role as binding inhibitors
in the “low T4 syndrome” of critically ill patients must be questioned. It cannot
be excluded that THBI assays demonstrating this inhibition measure artefacts caused
by heparine-induced in vitro lipolysis.
Thyroid hormone binding inhibition - Low T4 syndrome - Critical illness - Free fatty
acids
