1 Section of Orthopaedics and Internal Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 LUKKET: Klinikudvalget Københavns Amt, BSc + MSc programme, Faculty of Health and Medical Sciences, Københavns Universitet3 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet4 unknown5 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
A Diagnostic Dilemma
During follow-up on patients treated for differentiated thyroid cancer, thyroglobulin (Tg) antibodies can interfere with the Tg assay, making the use of Tg less reliable as a tumor marker. Purpose: To compare Tg and Tg autoantibodies (Tg- Ab) methods used in Denmark, regarding the number of patient samples being accepted for evaluating the result of a serum thyroglobulin (s-Tg) measurement. Design: 95 consecutive blood samples drawn from patients in 2006 in one center were selected according to the following criteria: s-Tg ! 1g/l and accepted BRAHMS Tg+ recovery test using 50 ng of Tg. Samples were retested with: (1) DPC IMMULITE 2000 Tg and Tg-Ab, (2) BRAHMS Tg and Tg-Ab on Kryptor, (3) BRAHMS Tg+ and Dynotest anti-Tg, (4) DELFIA hTg and recovery test using 25 ng of Tg, and (5) BRAHMS Tg+ with recovery test using 1 and 50 ng of Tg. Results: The number of patient samples that was not accepted for Tg evaluation varied from 2 to 26% when the reference values suggested by the manufacturers of the assay were used. When using the detection limit to the cutoff seen in epidemiological studies the number increased to 40%. Conclusion: We found large discrepancies in acceptance of patient samples for s-Tg evaluation, thus illustrating a diagnostic dilemma.
European Thyroid Journal, 2012, Vol 1, Issue 3, p. 193-197