Updated July 17. 2006
The Laboratory Services Committee of the American Thyroid Association alerts physicians that the Nichols Advantage Thyroglobulin Assay which has been used by many major laboratories across the country has become permanently unavailable.
For patients with thyroid cancer, the accurate measurement of serum thyroglobulin is an essential monitoring tool. The absence of detectable thyroglobulin in a patient’s blood is a good sign that the disease is in remission, while an increase in the thyroglobulin level may indicate that the cancer remains or is growing. Since thyroglobulin assay methods are not interchangeable, results using a new assay may not be directly comparable to the previous assay. A recent publication describes the potential differences in reported thyroglobulin levels between assay methods (1).
Patients who are due to have their thyroglobulin level measured should ask their physicians if the thyroglobulin assay method they intend to use has changed. Physicians should ask their clinical laboratory if a new thyroglobulin assay is being substituted, and if so, how the results compare to those previously obtained.
(1) Spencer CA, Bergoglio LM, Kazarosyan M, Fatemi S, Lopresti JS 2005 Clinical Impact of Thyroglobulin (Tg) and Tg autoantibody Method Differences on the Management of patients with Differentiated Thyroid Carcinomas. J Clin Endocrinol Metab 90:5566-7