A simple, rapid and precise automated method for the determination of T3-uptake.

A method is described for the automation of the T3-uptake test using a discrete analyser. This enables 160 samples to be analysed in two hours at a cost of only 9p a sample. By making use of a simple correction procedure for differences in charcoal contact time and for radioactive carryover it is possible to get a within-batch precision of 2.5% and a between-batch precision of 4.6% for values within the normal range.