Analysis index

1 ml serum, frozen
A cool box will be issued on request.

Men: 1,0 – 11,8 ng/l

High-sensitivity assay: 0,5 – 9,5 ng/l

Women: 1,0 – 4,8 ng/l

High-sensitivity assay: 0,5 – 6,4 ng/l

Clarification of thyroid nodules, detection and monitoring of c-cell carcinoma (= medullary carcinoma, MTC), familial tests in patients with confirmed MTC or suspicion of multiple endocrine neoplasia type II (MEN II).

Please also refer to: Ret-proto oncogene

The medullary thyroid carcinoma (MTC) occurs sporadically in 75 % of cases and in 25% of cases in the context of hereditary MEN 2.

The disease entity of an isolated familial medullary thyroid carcinoma (FMTC) is presumably a variant of MEN 2A, in which no pheochromocytoma nor primary hyperparathyroidism is seen. Increased values are measured in our laboratory with a high-sensitive immunoassay, which usually allows a reliable diagnosis of MTC (women > 30 ng/l, men > 60 ng/l) even without stimulation tests (i. e. calcium stimulation test). In case of doubt (women 20 – 30 ng/l, men 30 – 60 ng/l), the additional determination of CEA and chromogranin A can be useful. Decisive in these cases however is the progress check after 3 – 6 months. On suspicion of MEN 2, a molecular genetic analysis of the Ret-proto oncogene (see there) should be done.

False-positive results of the calcitonin value, which are usually below 26 ng/l in the high-sensitive assay, are seen in case of hypercalcemia (for instance in the context of primary hyperparathyroidism), hypergastrinemia, other neuroendocrine tumors, renal insufficiency, papillary and follicular thyroid carcinomas as concomitant reaction, struma diffusa or nodosa and chronic autoimmune thyroid disease of the Hashimoto type. In addition, corticoid therapy, proton pump inhibitors (treatment over 2 months) and beta-blockers may lead to hypercalcitonemia. Macro-calcitonin development due to antibodies is also possible; this however will lead to considerably higher values and should be ruled out as the differential diagnosis to the MTC in case of clinical doubt.