scholarly journals Improving the Dutch Newborn Screening for Central Congenital Hypothyroidism by Using 95% Reference Intervals for Thyroxine-Binding Globulin

2021 ◽  
pp. 1-8
Author(s):  
Kevin Stroek ◽  
Annemieke C. Heijboer ◽  
Marja van Veen-Sijne ◽  
Annet M. Bosch ◽  
Catharina P.B. van der Ploeg ◽  
...  

Introduction: Newborn screening (NBS) for congenital hypothyroidism (CH) in the Netherlands consists of thyroxine (T4), thyroid-stimulating hormone (TSH), and T4-binding globulin (TBG) measurements to detect thyroidal CH and central CH (CH-C). CH-C is detected by T4 or a calculated T4/TBG ratio, which serves as an indirect measure of free T4. TSH and TBG are only measured in the lowest 20 and 5% of daily T4 values, respectively. A recent evaluation of the Dutch NBS for CH showed that the T4 and T4/TBG ratio contribute to the detection of CH-C but also lead to a low positive predictive value (PPV). Dried blood spot (DBS) reference intervals (RIs) are currently unknown and may contribute to improvement of our NBS algorithm. Materials and Methods: RIs of T4, TSH, TBG, and the T4/TBG ratio were determined according to Clinical &amp; Laboratory Standards Institute guidelines in heel puncture cards from routine NBS in both sexes and at the common NBS sampling ages. Scatter plots were used to compare the healthy reference population to previously published data of CH-C patients and false positives. Results: Analyses of 1,670 heel puncture cards showed small differences between subgroups and led to the formulation of total sample DBS RIs for T4 (56–118 nmol/L), TSH (<2.6 mIU/L), TBG (116–271 nmol/L), and the T4/TBG ratio (>20). 46% of false-positive referrals based on T4 alone had a TBG below the RI, indicating preventable referral due to partial TBG deficiency. One case of CH-C also had partial TBG deficiency (TBG 59 and T4 12 nmol/L blood). Discussion/Conclusion: Established DBS RIs provided possibilities to improve the PPV of the Dutch CH NBS algorithm. We conclude that by taking partial TBG deficiency into account, approximately half of T4 false-positive referrals may be prevented while maintaining NBS sensitivity at the current level.

2020 ◽  
Vol 183 (3) ◽  
pp. 265-273
Author(s):  
Kevin Stroek ◽  
Annemieke C Heijboer ◽  
Marelle J Bouva ◽  
Catharina P B van der Ploeg ◽  
Marie-Louise A Heijnen ◽  
...  

Objective: Congenital hypothyroidism (CH) is defined as thyroid hormone deficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pituitary (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 thyroxine-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serves 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 using a database of referred cases by assessing the contribution of each criterion in the unique stepwise T4-TSH-TBG NBS algorithm. Results: Between 2007 and the end of 2017, 1 963 465 newborns were screened 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 cases by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T4-TSH-TBG NBS algorithm was 21.0%. Conclusion: This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS algorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the Netherlands, at the cost of a lower PPV compared to TSH-based NBS strategies.


2021 ◽  
Vol 7 (3) ◽  
pp. 34
Author(s):  
Kanshi Minamitani

Congenital hypothyroidism (CH) is the most common preventable cause of intellectual impairment or failure to thrive by early identification and treatment. In Japan, newborn screening programs for CH were introduced in 1979, and the clinical guidelines for newborn screening of CH were developed in 1998, revised in 2014, and are currently undergoing further revision. Newborn screening strategies are designed to detect the elevated levels of thyroid stimulating hormone (TSH) in most areas of Japan, although TSH and free thyroxine (FT4) are often measured simultaneously in some areas. Since 1987, in order not to observe the delayed rise in TSH, additional rescreening of premature neonates and low birth weight infants (<2000 g) at four weeks of life or when their body weight reaches 2500 g has been recommended, despite a normal initial newborn screening. Recently, the actual incidence of CH has doubled to approximately 1:2500 in Japan as in other countries. This increasing incidence is speculated to be mainly due to an increase in the number of mildly affected patients detected by the generalized lowering of TSH screening cutoffs and an increase in the number of preterm or low birth weight neonates at a higher risk of having CH than term infants.


2021 ◽  
pp. 1-8
Author(s):  
Niamh McGrath ◽  
Colin Patrick Hawkes ◽  
Stephanie Ryan ◽  
Philip Mayne ◽  
Nuala Murphy

Scintigraphy using technetium-99m (<sup>99m</sup>Tc) is the gold standard for imaging the thyroid gland in infants with congenital hypothyroidism (CHT) and is the most reliable method of diagnosing an ectopic thyroid gland. One of the limitations of scintigraphy is the possibility that no uptake is detected despite the presence of thyroid tissue, leading to the spurious diagnosis of athyreosis. Thyroid ultrasound is a useful adjunct to detect thyroid tissue in the absence of <sup>99m</sup>Tc uptake. <b><i>Aims:</i></b> We aimed to describe the incidence of sonographically detectable in situ thyroid glands in infants scintigraphically diagnosed with athyreosis using <sup>99m</sup>Tc and to describe the clinical characteristics and natural history in these infants. <b><i>Methods:</i></b> The newborn screening records of all infants diagnosed with CHT between 2007 and 2016 were reviewed. Those diagnosed with CHT and athyreosis confirmed on scintigraphy were invited to attend a thyroid ultrasound. <b><i>Results:</i></b> Of the 488 infants diagnosed with CHT during the study period, 18/73 (24.6%) infants with absent uptake on scintigraphy had thyroid tissue visualised on ultrasound (3 hypoplastic thyroid glands and 15 eutopic glands). The median serum thyroid-stimulating hormone (TSH) concentration at diagnosis was significantly lower than that in infants with confirmed athyreosis (no gland on ultrasound and no uptake on scintigraphy) (74 vs. 270 mU/L), and median free T4 concentration at diagnosis was higher (11.9 vs. 3.9 pmol/L). Six of 10 (60%) infants with no uptake on scintigraphy but a eutopic gland on ultrasound had transient CHT. <b><i>Conclusion:</i></b> Absent uptake on scintigraphy in infants with CHT does not rule out a eutopic gland, especially in infants with less elevated TSH concentrations. Clinically, adding thyroid ultrasound to the diagnostic evaluation of infants who have athyreosis on scintigraphy may avoid committing some infants with presumed athyreosis to lifelong levothyroxine treatment.


2015 ◽  
Vol 2 ◽  
pp. 2333794X1456719 ◽  
Author(s):  
Xin Fan ◽  
Shaoke Chen ◽  
Jiale Qian ◽  
Suren Sooranna ◽  
Jingi Luo ◽  
...  

Background. A newborn screening program (NSP) for congenital hypothyroidism (CH) was carried out in Guangxi in order to understand the incidence of CH and the factors interrelated to major types of CH in this region of China. Methods. During 2009 to 2013, data from 930 612 newborns attending NSP in Guangxi were collected. Patients were classified with either permanent CH (PCH) or transient CH (TCH) after 2 years of progressive study. Results. A total of 1210 patients were confirmed with CH with an incidence of 1/769, including 68 PCH and 126 TCH cases with incidences of 1/6673 and 1/3385, respectively. The frequency of thyroid stimulating hormone values greater than 5 mIU/L was 7.2%, which, based on WHO guidelines, suggests that the population was mildly iodine deficient. Conclusions. The incidence of CH was high in Guangxi. Approximately two thirds of CH patients were TCH, which may be due to a deficiency in iodine within the population.


2019 ◽  
Vol 09 (01) ◽  
pp. 040-044 ◽  
Author(s):  
Jyotsna Verma ◽  
Papai Roy ◽  
Divya C. Thomas ◽  
Geetu Jhingan ◽  
Azad Singh ◽  
...  

AbstractNewborn screening (NBS) aims toward early detection of treatable congenital disorders. From January 2008 through December 2017, 13,376 newborns were screened for congenital hypothyroidism (CH), congenital adrenal hyperplasia (CAH), and glucose-6-phosphate dehydrogenase (G6PD) deficiency at Sir Ganga Ram Hospital, India, by measuring G6PD activity, thyroid-stimulating hormone, and 17-hydroxyprogesterone on dried blood specimens. The birth prevalence of 1:2,000 for CH, 1:2,500 for CAH, and 1:125 for G6PD deficiency indicates the latter as the most prevalent. Performance evaluation of testing reveals a robust screening program with 100% sensitivity and >99% specificity. Hence, we recommend NBS for early diagnosis and treatment to prevent adverse outcomes.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Viraj V Desai ◽  
Pratima V Kumar

Abstract Background: Pseudohypoparathyroidism 1B (PHP1B) is a disorder that can lead to thyroid stimulating hormone (TSH) resistance and hypothyroidism, although it is rarely associated with thyrotoxicosis. Clinical Case: A 25-year-old female with a history of PHP1B, seizures due to hypocalcemia, and family history of PHP1B in her three sisters and brother presented to our emergency room with a fever of 1030F and generalized malaise. Two months prior, she was seen at an outside hospital with palpitations and bulging of the left eye. There, she was diagnosed with hyperthyroidism, started on methimazole, and asked to continue levetiracetam and calcitriol upon discharge. On our exam, she had tachycardia of 120 beats per minute, left eye proptosis, positive Chvostek sign, and a large goiter with bruit. Reflexes were 3+. Laboratory evaluation revealed corrected serum calcium of 6.1 (8.5-10.5 mg/dL), TSH &lt; 0.01 (0.34-5.60 mU/L), free T4 2.81 (0.60-1.60 ng/dL), free T3 13.0 (2.4-4.2 ng/dL), and iPTH 131 (12-88 pg/mL). ELISA testing for screening of HIV was positive. She was treated with IV calcium gluconate, methimazole, propranolol, and hydrocortisone. Her home doses of calcitriol and calcium were resumed. She was referred for total thyroidectomy as an outpatient once she became euthyroid. The confirmatory Western blot test for HIV was negative. It was determined that presence of thyroid stimulating immunoglobulin resulted in the false positive ELISA test. Discussion: Hyperthyroidism with Graves disease seen in PHP has only very rarely been reported. (1) It has been postulated that abnormal electrolytes and elevated parathyroid hormone from PHP may lead to stimulation of the thyroid gland and perpetuate Graves disease symptoms. (2) Furthermore, the presentation of thyrotoxicosis despite TSH resistance in PHP indicates that there may be other mechanisms for TSH receptor antibodies to take effect in these patients which have not yet been determined. (3) Lastly, autoimmune diseases, including Graves disease, can cause a false-positive HIV ELISA as seen in our patient. Conclusion: Although rare, thyrotoxicosis may present in patients with PHP1B. Additionally, it should be kept in mind that autoimmune diseases such as Graves disease can cause a false positive HIV ELISA, and follow-up Western blot testing should therefore be performed. References: (1) Gerhardt A, Hackenberg K. 2002. Pseudohypoparathyroidism and Graves’ disease: a rare combination of two endocrinological diseases. Exp Clin Endocrinol Diabetes. 110:245-247 (2) Morón-Díaz et al. 2019. A rare case of Graves’ disease in a patient with type 1B pseudohypoparathyroidism and associated TSH resistance. Endocrine Abstracts. 63:96 (3) Richard Prokesch. 2010. Navigating False Positive Testing. HIV Specialist (AAHIVS). 2:27


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