Abstract

Serum levels of free thyroxine (T4) are helpful in the clinical evaluation of patients who are suspected of having thyroid disease, since free T4 (unbound) is known to closely relate to hyper, eu and hypothyroidism. There are documented inconsistencies among commercially available direct free thyroxine immunoassays. The biochemical basis for these inconsistencies is not understood and has not been characterized. Direct free T4 measurements have been linked to both T4-binding serum protein concentrations and protein-bound T4 concentrations. A free T4 reference method using direct equilibrium dialysis radioimmunoassay has been well characterized. New experiments have applied this equilibrium dialysis reference method and a well characterized total T4 immunoassay to the characterization of eight commercially available direct free T4 immunoassays. The data contained in this dissertation show that these direct free T4 determinations correlate with protein-bound T4 concentrations, total T4 concentrations or both. These direct free T4 immunoassays are non-specific, insensitive and inaccurate when used to measure normal levels of free thyroxine in serum.

LLU Discipline

Biochemistry

Department

Biochemistry

School

Graduate School

First Advisor

R. Bruce Wilcox

Second Advisor

Danilan Angeles

Third Advisor

Jonathan Neidigh

Fourth Advisor

Jerald C. Nelson

Fifth Advisor

Lawrence Sower

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

2007

Date (Title Page)

5-2007

Language

English

Library of Congress/MESH Subject Headings

Thyroid Diseases; Thyroxine -- chemistry; Thyroid Hormones

Type

Dissertation

Page Count

xi; 122

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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