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The following is a summary of “Defining the Functional Sensitivity for the Siemens Atellica Calcitonin Assay: Insight From a Single-Center Study,” published in the August 2024 issue of Endocrinology by Li et al.

Detectable and especially rising serum calcitonin and carcinoembryonic antigen (CEA) levels following thyroidectomy are critical indicators of potential disease presence in patients with medullary thyroid carcinoma, as outlined by American Thyroid Association guidelines. This necessitates regular monitoring of calcitonin levels or imaging studies to detect persistent or recurrent disease early. Establishing a clinical cutoff value for calcitonin assays, about imaging and the patient’s clinical status, is vital for optimizing patient care. The present study aimed to evaluate postoperative calcitonin levels using the Siemens Atellica assay system to determine the most appropriate threshold for clinical decision-making. 

Researchers conducted a retrospective analysis of calcitonin testing on 56 samples from 40 patients collected between September 27, 2022, and August 11, 2023. The analysis focused solely on calcitonin results obtained at least three months post-total thyroidectomy, and corresponding imaging studies performed within six months of the calcitonin report were assessed. Additionally, carcinoembryonic antigen results were reviewed to provide a comprehensive evaluation. Precision analysis of calcitonin measurements at 2.94 and 5.24 pg/mL yielded coefficients of variation of 16.49% and 8.87%, respectively. 

For identifying post-total thyroidectomy persistent or recurrent medullary thyroid carcinoma as confirmed by imaging, a calcitonin cutoff of 1.89 pg/mL demonstrated 43% sensitivity and 67% specificity. Conversely, a higher 5.00 pg/mL cutoff resulted in 0% sensitivity but 100% specificity. These findings suggest that a calcitonin cutoff of 5 pg/mL on the Siemens Atellica platform may be a suitable threshold for evaluating tumor persistence or recurrence in patients following thyroidectomy within the institution. Nonetheless, individual laboratories must establish their clinical cutoff values for calcitonin monitoring to ensure an accurate assessment of tumor recurrence in postoperative patient management. This study underscores the importance of tailored approaches to patient care and the need for standardized yet adaptable guidelines for monitoring calcitonin levels in medullary thyroid carcinoma survivors.

Source: sciencedirect.com/science/article/abs/pii/S1530891X24006566