[Comparative studies of commercially available T4-RIA-kits (author's transl)]

The investigation of 4 commercially available T4-RIA-Kits with 350 patient sera have shown that: The separation of hypo-, eu- and hyperthyroid values is easier with kit a) and d) than with b) and c), though all kits give acceptable values under routine conditions. For the determination of the "normal range" not less than 100 patient sera are necessary. The time needed for 100 determinations is 2 to 3 hr. A general recommendation for one of the tested T4-RIA-Kits cannot be made since the choice depends also on local circumstances.