Toxic multinodular goiter laboratory findings

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

Overview

Diagnosis of multinodular goiter is made by measurement of serum thyroid-stimulating hormone (TSH) , serum free T4 test , total thyroxine (T4) and free triiodothyronine (T3).

Laboratory Findings

Diagnosis of multinodular goiter is made by measurement of serum thyroid-stimulating hormone (TSH) , serum free T4 test , total thyroxine (T4) and free triiodothyronine (T3).^[1]
Additional tests include:
- Serum thyroglobulin and thyroid autoantibodies to detect autoimmunity that may co-exist with goiter and lung function testing.
- Urinary iodine excretion can be measured in case of suspected iodine excess.
Laboratory findings consistent with the diagnosis of multinodular goiter include:^[2]
- TSH is usually normal or decreased.
- Free T4, and free T3 is usually normal or elevated.
- An isolated increase in T4 is observed in:
  - Hyperthyroidism induced by iodine
  - Hyperthyroidism due to agents that reduce peripheral conversion of T4 to triiodothyronine (T3) like:^[1]
- Serum thyroglobulin is usually elevated.
- Thyroid autoantibodies (thyroperoxidase antibodies and thyroglobulin antibody) usually negative.
- Some patients with multinodular goiter may have impaired inspiratory capacity on lung function testing.

References

↑ ^1.0 ^1.1 Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, Pacini F, Randolph GW, Sawka AM, Schlumberger M, Schuff KG, Sherman SI, Sosa JA, Steward DL, Tuttle RM, Wartofsky L (2016). “2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer”. Thyroid. 26 (1): 1–133. doi:10.1089/thy.2015.0020. PMC 4739132. PMID 26462967.
↑ Hegedüs L, Bonnema SJ, Bennedbaek FN (2003). “Management of simple nodular goiter: current status and future perspectives”. Endocr. Rev. 24 (1): 102–32. doi:10.1210/er.2002-0016. PMID 12588812.

Overview