RT Journal Article
SR Electronic
T1 Choice of Reference Sera for Measurement of Effective Thyroxine Ratio
JF Journal of Nuclear Medicine Technology
JO J. Nucl. Med. Technol.
FD Society of Nuclear Medicine
SP 69
OP 72
VO 6
IS 2
A1 Witte, David L.
A1 Persoon, Thomas J.
A1 Bible, Keith
A1 Routh, Joseph I.
YR 1978
UL http://tech.snmjournals.org/content/6/2/69.abstract
AB The measurement of combined T3U and T4D by the use of effective thyroxine ratio (ETR), compensated thyroxine (CT4), or normalized thyroxine (NT4) systems has become commonplace. All these methods rely on comparison of individual patient results to a euthyroid reference serum; however, little has been published regarding the requirements of an acceptable euthyroid reference serum. Measurement of T3U, T4D, and ETR using acid denaturation in sera with varying T3U and T4D indicates that ETR is systematically dependent on total T4 concentration, but relatively insensitive to thyroxine binding globuliff level. In selecting an appropriate euthyroid reference serum for either ETR, NT4, or CT4 procedures, the T4 value must be scrutinized, whereas T3U is of less importance. If successive reference sera are not carefully selected, the published reference ranges from normal populations could be invalid.