Akademik Veri Yönetim Sistemi
XXXIII. WASPaLM World Congress & XXIV. National Clinicial Biochemistry Congress , Antalya, Türkiye, 16 - 20 Ekim 2024, ss.161, (Özet Bildiri)
Aim: Serum thyroglobulin immunometric assay (Tg-IMA) techniques, essential for evaluating treatment response in Differentiated Thyroid Cancer (DTC), are influenced by thyroglobulin autoantibodies (TgAb), affecting result accuracy. In this investigation, different Tg-IMAs were compared using quantitative approach following American Thyroid Association (ATA) and Clinical and Laboratory Standards Institute (CLSI) EP09c guidelines. Methods: A total of 249 serum samples were tested with four Tg-IMA methods: Abbott Architect, Beckman Access, Roche Cobas Elecsys (second-generation), and Siemens Immulite (first-generation). Passing-Bablok, Folded Probability analyses were performed. Results: Second-generation Tg-IMA methods demonstrated strong correlations (r>0.884) across all concentration levels (≤1, 1-10, >10 ng/mL), although biases of up to 2-fold were observed at different Tg levels (slope:1.131-2.027). Correlations between the Siemens Immulite Tg and second-generation Tg methods were observed to be strong at concentrations >10 ng/mL (r>0.945), but less so at lower concentrations (r<0.642). Negative interference from TgAb notably affects Siemens Immulite Tg. Conclusion: Second-generation Tg-IMA methods yield highly correlated results at all levels, including low Tg concentration subgroups. However, it is noteworthy that the Tg results obtained from these methods for the same patient sample exhibit proportional biases at levels that render them unsuitable for comparison with each other. Nevertheless, Siemens Immulite Tg exhibited negligible and weak correlations with second-generation Tg assays at Tg concentrations below 10 ng/mL, indicating that the limit of quantification (LoQ) for Siemens Immulite Tg may require recalculation. Additionally, Siemens Immulite Tg is more susceptible to negative interference from TgAb compared to the other three Tg assays, a factor that should be carefully considered in the clinical management of patients with DTC.It is crucial to underscore that serum Tg measurements are a valuable tool for monitoring cancer recurrence in patients with DTC after surgical and/or radioactive iodine (RAI) treatments. They provide insight into the biochemical aspects of patient follow-up, which is pivotal for effective surveillance and management of this disease. In particular, collaboration between clinicians and clinical biochemists will be beneficial in identifying potential issues in the interpretation of Tg tests that exhibit significant differences in analytical methodology.