Effects of Anti-thyroglobulin Antibody on the Measurement of Thyroglobulin : Differences Between Immunoradiometric Assay Kits Available

면역방사계수법을 이용한 Thyroglobulin 측정시 항 Thyroglobulin 항체의 존재가 미치는 영향: Thyroglobulin 측정 키트에 따른 차이

  • Ahn, Byeong-Cheol (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Seo, Ji-Hyeong (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Bae, Jin-Ho (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Jeong, Shin-Young (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Yoo, Jeong-Soo (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Jung, Jin-Hyang (Department of General Surgery, School of Medicine, Kyungpook National University) ;
  • Park, Ho-Yong (Department of General Surgery, School of Medicine, Kyungpook National University) ;
  • Kim, Jung-Guk (Department of Internal Medicine, School of Medicine, Kyungpook National University) ;
  • Ha, Sung-Woo (Department of Internal Medicine, School of Medicine, Kyungpook National University) ;
  • Sohn, Jin-Ho (Department of Otolayngology, School of Medicine, Kyungpook National University) ;
  • Lee, In-Kyu (Department of Internal Medicine, School of Medicine, Kyungpook National University) ;
  • Lee, Jae-Tae (Department of Nuclear Medicine, School of Medicine, Kyungpook National University) ;
  • Kim, Bo-Wan (Department of Internal Medicine, School of Medicine, Kyungpook National University)
  • 안병철 (경북대학교 의과대학 핵의학교실) ;
  • 서지형 (경북대학교 의과대학 핵의학교실) ;
  • 배진호 (경북대학교 의과대학 핵의학교실) ;
  • 정신영 (경북대학교 의과대학 핵의학교실) ;
  • 유정수 (경북대학교 의과대학 핵의학교실) ;
  • 정진향 (경북대학교 의과대학 외과학교실) ;
  • 박호용 (경북대학교 의과대학 외과학교실) ;
  • 김정국 (경북대학교 의과대학 내과학교실) ;
  • 하승우 (경북대학교 의과대학 내과학교실) ;
  • 손진호 (경북대학교 의과대학 이비인후과학교실) ;
  • 이인규 (경북대학교 의과대학 내과학교실) ;
  • 이재태 (경북대학교 의과대학 핵의학교실) ;
  • 김보완 (경북대학교 의과대학 내과학교실)
  • Published : 2005.08.31

Abstract

Purpose: Thyroglobulin (Tg) is a valuable and sensitive tool as a marker for diagnosis and follow-up for several thyroid disorders, especially, in the follow-up of patients with differentiated thyroid cancer (DTC). Often, clinical decisions rely entirely on the serum Tg concentration. But the Tg assay is one of the most challenging laboratory measurements to perform accurately owing to antithyroglobulin antibody (Anti-Tg). In this study, we have compared the degree of Anti-Tg effects on the measurement of Tg between availale Tg measuring kits. Materials and Methods: Measurement of Tg levels for standard Tg solution was performed with two different kits commercially available (A/B kits) using immunoradiometric assay technique either with absence or presence of three different concentrations of Anti-Tg. Measurement of Tg for patient's serum was also performed with the same kits. Patient's serum samples were prepared with mixtures of a serum containing high Tg levels and a serum containg high Anti-Tg concentrations. Results: In the measurements of standard Tg solution, presence of Anti-Tg resulted in falsely lower Tg level by both A and B kits. Degree of Tg underestimation by h kit was more prominent than B kit. The degree of underestimation by B kit was trivial therefore clinically insignificant, but statistically significant. Addition of Anti-Tg to patient serum resulted in falsely lower Tg levels with only A kit. Conclusion: Tg level could be underestimated in the presence of anti-Tg. Anti-Tg effect on Tg measurement was variable according to assay kit used. Therefore, accuracy test must be performed for individual Tg-assay kit.

References

  1. Medeiros-Neto G, Targovnik HM, Vassart G. Defective thyroglobulin synthesis and secretion causing goiter and hypothyroidism. Endocr Rev 1993;14:165-83
  2. Torrens JI, Burch HB. Serum thyroglobulin measurement. Utility in clinical practice. Endocrinol Metab Clin North Am 2001;30: 429-67 https://doi.org/10.1016/S0889-8529(05)70194-8
  3. Kinder BK. Well differentiated thyroid cancer. Curr Opin Oncol 2003;15:71-77 https://doi.org/10.1097/00001622-200301000-00011
  4. Spencer CA, Takeuchi M, Kazarosyan M, Wang CC, Guttier RB, Singer PA et al. Serum thyroglobulin autoantibodies: prevalence, influence on serum thyroglobulin measurement, and prognostic significance in patients with differentiated thyroid carcinoma. J Clin Endocrinol Metab 1998;83:1121-7 https://doi.org/10.1210/jc.83.4.1121
  5. McDougall IR. Management of thyroglobulin positive/whole-body scan negative: is Tg $positive/^{131}$ therapy useful? J Endocrinol Invest 2001;24:194-8 https://doi.org/10.1007/BF03343843
  6. Ahn BC, Bae JH, Jeong SY, Park HY, Kim JK, Ha SW et al, Influence of anti-thyroglobulin antibody on the measurement of thyroglobulin using the immunoradiometric assay. J Korean Society Endocrinol 2004;19:42-7
  7. Park. Y J. The measurement of serum thyroglobulin levels. J Korean Society Endocrinol 2004;19:120-6
  8. Wilson R, McKillop JH, Jenkins C, Beastall GH, Thomson JA. Serum Thyroglobulin Kits measurement and clinical use. Ann Clin Biochem 1989;26:401-6 https://doi.org/10.1177/000456328902600504
  9. Chung JK, Park YJ, Kim TY, So Y, Kim SK, Park DJ et al. Clinical significance of elevated level of serum antithyroglobulin antibody in patients with differentiated thyroid cancer after thyroid ablation. Clin Endocrinol 2002;57:215-21 https://doi.org/10.1046/j.1365-2265.2002.01592.x
  10. Schlumberger MJ. Diagnostic follow-up of well-differentiated thyroid carcinoma: historical perspective and current status. J Endocrinol Invest 1999;22:3-7
  11. Feldt-Rasmussen U, Hegedus L, Perrild H, Rasmussen N, Hansen JM. Relationship between serum thyroglobulin, thyroid volume and serum TSH in healthy non-goitrous subjects and the relationship to seasonal variations in iodine intake. Thyroulology 1989; 1: 115-8
  12. Rubello D, Casara D, Girelli ME, Piccolo M, Busnardo B. Clinical meaning of circulating antithyroglobulin antibodies in differentiated thyroid cancer: a prospective study. J Nud Med 1992;33:1478-80
  13. Brown TR, Zhao G, Pamer KC, Sundick RS. Thyroid injury, autoantigen availability, and the initiation of autoimmune thyroiditis. Autoimmunity 1998;27:1-12
  14. Weightman DR, Mallick UK, Fenwick JD, Perros P. Discordant serum thyroglobulin results generated by two classes of assay in patients with thyroid carcinoma: correlation with clinical outcome after 3 years of follow-up. Cancer 2003;98:41-7 https://doi.org/10.1002/cncr.11472
  15. Bourrel F, Hoff M, Regis H, Courriere P, Caron P. Immunoradiometric assay of thyroglobulin in patients with differentiated thyroid carcinomas: need for thyroglobulin recovery tests. Clin Chem Lab Med 1998;36:725-30 https://doi.org/10.1515/CCLM.1998.128
  16. Ferrari L, Biancolini D, Seregni E, Aliberti G, Martinetti A, Villano C et al. Critical aspects of immunoradiometric thyroglobulin assays. Tumori 2003;89:537-9
  17. Spencer CA, Takeuchi M, Kazarosyan M. Current status and performance goals for serum thyroglobulin assays. Clin Chem 1996;42:164-73
  18. Mariotti S, Barbesino G, Caturegli P, Marino M, Manetti L, Pacini F et al. Assay of thyroglobulin in serum with thyroglobulin autoantibodies: an unobtainable goal? J Clin Endocrinol Metab 1995;80:468-42 https://doi.org/10.1210/jc.80.2.468