Diagnosis and Management of Thyroid Nodules and Cancer Focus on Thyroglobulin

This presentation will focus on thyroid nodules and the laboratory tests used to distinguish benign from cancerous nodules. Measurement of thyroglobulin (Tg) is not used in the diagnosis of differentiated thyroid cancer, but is used to monitor recurrence of cancer in patients after treatment with thyroidectomy and ablation with radioiodine. Tg is therefore a biomarker for thyroid cancer recurrence. In persons with who produce antibodies to Tg(antiTg), there is interference with the immmunoassay of Tg, causing either false positive or negative results. We have circumvented the antibody interference by measurement of Tg by developing an LC/MS/MS assay that provides reliable results in the presence of the antiTg.

Lecture Presenters
A. Wayne Meikle, MD
A. Wayne Meikle, MD
Medical Director, Special Chemistry Laboratory, ARUP Laboratories
Assistant Professor of Pathology, University of Utah School of Medicine

Dr. Meikle is the medical director of the Endocrinology and Automated Endocrinology laboratories at ARUP and a professor of medicine, endocrinology, and pathology at the University of Utah School of Medicine. Dr. Meikle is a fellow of the American College of Physicians and the American College of Clinical Endocrinology, as well as a diplomate of the American Board of Internal Medicine. He is the associate editor of the reproductive endocrinology section of the Year Book of Endocrinology and editor of Endocrine Replacement Therapy in Clinical Practice. Dr. Meikle received his MD from the Vanderbilt University School of Medicine and is board certified in internal medicine, endocrinology, and metabolism.

Alan L. Rockwood, PhD
Alan L. Rockwood, PhD
Medical Director, Special Chemistry Laboratory, ARUP Laboratories
Assistant Professor of Pathology, University of Utah School of Medicine

Dr. Rockwood is the scientific director of the Mass Spectrometry Laboratory at ARUP, and a clinical associate professor of pathology at the University of Utah School of Medicine. He is a member of the American Association for Clinical Chemistry, American Society for Mass Spectrometry, and the Indian Society for Mass Spectrometry. Dr. Rockwood received his PhD in chemistry from Utah State University.

Objectives

After this presentation, participants will be able to:

Know the main causes of thyroid nodules.
Describe your approach to distinguish benign from malignant thyroid nodules.
Outline the usefulness of thyroglobulin measurements and recognize possible interference with the measurement for patients with antithyroglobulin antibodies.
Understand the relevant concepts of tandem mass spectrometry and liquid chromatography-tandem mass spectrometry.
Describe the use of a peptide generated by tryptic digestion of thyroglobulin as surrogate for thyroglobulin analysis (SISCAPA technique).
Explain how the described method removes autoantibody interferences.