TY - JOUR
AU - Law,, Terence
AB - Case Description A 20-month-old girl came to the endocrine clinic for a follow-up of her congenital hypothyroidism. She appeared well with no signs of hypo- or hyperthyroidism. The results of her thyroid function tests (Roche cobas c 501 analyzer) were as follows: free thyroxine (T4),2 11.2 ng/L (reference interval, 8.0–18.0 ng/L); thyroid-stimulating hormone (TSH), 185.2 mU/L (reference interval, 0.800–8.200 mU/L). The patient was receiving levothyroxine treatment, and the results of her previous free T4 and TSH tests, which were performed at another laboratory just 40 days before this visit, were within the reference intervals. Questions What are some possible explanations for the unexpectedly high TSH value in this patient? What is the most likely explanation and why? What really caused the unexpectedly high TSH value in this patient? The answers are below. Answers A mislabeled sample or the presence of heterophile antibodies was possible. This unique combination of a critically high TSH and a normal free T4 concentration, however, made a mislabeled sample unlikely. On the other hand, the absence of such a TSH increase in the patient as recently as 4 months earlier suggested no heterophile antibody interference. Medication noncompliance was also possible. We discussed the case with the clinician. Further investigation revealed the cause of the increased TSH. The father of the patient had recently started administering the patient’s levothyroxine dose by dissolving it in a full bottle of milk, which she did not always finish. A week after proper medication instructions were given, the patient’s TSH concentration decreased to 10.4 mU/L. 2 Nonstandard abbreviations: T4, thyroxine; TSH, thyroid-stimulating hormone. Author Contributions:All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article. Authors’ Disclosures of Potential Conflicts of Interest:No authors declared any potential conflicts of interest. Role of Sponsor: The funding organizations played no role in the design of study, choice of enrolled patients, review and interpretation of data, or preparation or approval of manuscript. © 2010 The American Association for Clinical Chemistry This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
TI - What Is Your Guess? Unexpectedly High Thyroid-Stimulating Hormone—Another Case of Heterophile Antibody?
JO - Clinical Chemistry
DO - 10.1373/clinchem.2010.148411
DA - 2010-07-01
UR - https://www.deepdyve.com/lp/oxford-university-press/what-is-your-guess-unexpectedly-high-thyroid-stimulating-hormone-6UGepIhumD
SP - 1203
VL - 56
IS - 7
DP - DeepDyve
ER -