Progress in laboratory testing of thyroid disease

Metrologic traceability of total thyroxine measurements in human serum: efforts to establish a network of Reference Measurement Laboratories.

Thienpont LM, Van Uytfanghe K, Marriot J, Stokes P, Siekmann L, Kessler A, Bunk D, Tai S. Clin Chem 2005;51:161-8.