Medullary thyroid cancer laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]

Overview

Laboratory findings consistent with the diagnosis of medullary thyroid cancer include decreased thyroid stimulating hormone, elevated calcitonin, and decreased calcium.

Blood or imaging tests may be done prior to or in lieu of a biopsy. The following blood tests are conducted:

Thyroid stimulating hormone (TSH)
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin- Calcitonin is required for the diagnosis and follow up of medullary thyroid cancer. It is an important tumor marker.
Carcinoembryonic antigen

Tests for serum thyroid autoantibodies are done to rule out autoimmune thyroid disease.
Laboratory findings consistent with the diagnosis of multiple endocrine neoplasia type 2 are tabulated below.

**Laboratory findings**
Test	Findings
Metabolic	Decreased thyroid stimulating hormone Antithyroid antibodies Elevated calcitonin Decreased calcium
Adapted from Arzu Tatlıpınar1 and İlkay Kartal [Updated 2015].The Evaluation of Thyroid Nodules. Journal of Thyroid Disorders & Therapy.2015.^[1]

Laboratory tests	Normal Range	Abnormal value
Serum
Thyroid stimulating hormone	0.4 – 4.0 milli-international units per liter	<0.4 or >4.0
Antithyroid antibodies	<35 IU/mL	>35 IU/mL
Serum calcitonin	less than 10pg/mL	>=100 pg/mL
Serum calcium	8.9-10.1 mg/dL	> 10.1 mg/dL or < 8.9 mg/dL

↑ İlkay Kartal, Arzu Tatlıpınar (2014). “The Evaluation of Thyroid Nodules”. Journal of Thyroid Disorders and Therapy. 04 (02). doi:10.4172/2167-7948.1000181. ISSN 2167-7948.