Abstract

Objective: Congenital hypothyroidism (CH) is defined as thyroid hormone de ficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pitu itary (central CH, CH-C). The Dutch Newborn Screening (NBS) strategy is primarily based on determination of thyroxine (T4) concentrations in dried blood spots followed, if necessary, by thyroid-stimulating hormone (TSH) and thyroxin e-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serv es as an indirect measure for free T4. A T4/TBG ratio . 17 in a second heel puncture is suggestive of CH-C. Design and methods: In the present study, we evaluated 11 years of Dutch CH NBS us ing a database of referred cases by assessing the contribution of each criterion in the unique s tepwise T4-TSH-TBG NBS algorithm. Results: Between 2007 and the end of 2017, 1 963 465 newborns were scre ened in the Netherlands. Use of the stepwise algorithm led to 3044 referrals and the identification of 612 CH cases, consisting of 496 CH-T, 86 CH-C, and 30 CH of unknown origin diagnoses. We detected 62.8% of CH-C ca ses by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T 4-TSH-TBG NBS algorithm was 21.0%. Conclusion: This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS a lgorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the N etherlands, at the cost of a lower PPV compared to TSHbased NBS strategies.

Original languageEnglish
Pages (from-to)265-273
Number of pages9
JournalEuropean journal of endocrinology
Volume183
Issue number3
DOIs
Publication statusPublished - 1 Sept 2020

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