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Papillary thyroid carcinoma follow-up — SCE Endocrinology MCQ

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HardThyroidPapillary thyroid carcinoma follow-upSCE Endocrinology

After total thyroidectomy for differentiated thyroid cancer, thyroglobulin is undetectable but anti-thyroglobulin antibodies are positive. How should biochemical surveillance be interpreted?

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Correct answer: CThyroglobulin interpreted alongside serial anti-thyroglobulin antibodies

The best answer is “Thyroglobulin interpreted alongside serial anti-thyroglobulin antibodies”. Anti-thyroglobulin antibodies can interfere with immunometric thyroglobulin measurement and make a falsely reassuring result; serial antibody trends and imaging context therefore matter. “Interpret undetectable thyroglobulin without accounting for assay interference” is less appropriate because assay interference prevents an undetectable value from standing alone “Replace thyroglobulin with calcitonin because antibodies are present” is less appropriate because calcitonin monitors medullary rather than differentiated thyroid cancer “Use TSH-receptor antibodies as the recurrence marker” is less appropriate because TSH-receptor antibodies assess Graves disease “Rely on urinary iodine as the sole tumour marker” is less appropriate because urinary iodine may inform preparation for radioiodine but is not the principal recurrence marker

Reference: NICE NG230: Thyroid cancer — assessment and management. https://www.nice.org.uk/guidance/ng230/chapter/Recommendations