The Impact of Seasonal Changes on Thyroxine and Thyroid-Stimulating Hormone in Newborns
Open Access
- 3 February 2021
- journal article
- research article
- Published by MDPI AG in International Journal of Neonatal Screening
- Vol. 7 (1), 8
- https://doi.org/10.3390/ijns7010008
Abstract
Newborn screening for congenital hypothyroidism (CH) is performed by measuring the concentration of thyroxine (T4) and/or thyroid-stimulating hormone (TSH) in dried blood spots. Unfortunately, the levels of T4 and TSH vary due to multiple factors, and therefore the false-positive rate for the test is a challenge. We analyzed screening data from 2008 to 2017 to determine the effect of seasonal changes and manufacturer kit lot changes on T4 and TSH values and on numbers of infants referred. Over a 10-year period, we screened 2.4 million infants using commercially available fluoroimmunoassays to measure T4 and TSH concentrations in dried blood spots. During colder months, daily mean T4 and TSH values were higher and referral rates and false-positive rates were higher. However, there was no significant difference between the number of confirmed CH cases. Furthermore, in rare instances, we observed differences in T4 daily mean values during the 10-year period when manufacturer kit lot changes were made. Seasonal temperature variations influence measured T4 and TSH values and consequently lower the positive predictive value for CH testing in colder months. Newborn screening (NBS) programs should be aware that manufacturer kit lot changes may also influence T4 values.Keywords
This publication has 40 references indexed in Scilit:
- Increasing Incidence, but Lack of Seasonality, of Elevated TSH Levels, on Newborn Screening, in the North of EnglandJournal of Thyroid Research, 2010
- Seasonality in the Incidence of Congenital Hypothyroidism in Japan: Gender-Specific Patterns and Correlation with TemperatureThyroid®, 2007
- Thyroid Function in Seventy-Five Healthy Preterm Infants Thirty to Thirty-Five Weeks of Gestational Age: A Prospective and Longitudinal Study During the First Year of LifeThyroid®, 2004
- Congenital hypothyroidism, seasonality and consanguinity in the West Midlands, EnglandActa Paediatrica, 1999
- Thyroid Function in the Preterm InfantThyroid®, 1999
- Thyroid Function in Very Preterm Newborns: Possible ImplicationsThyroid®, 1999
- Thyroid function in very low birth weight infants: Effects on neonatal hypothyroidism screeningThe Journal of Pediatrics, 1996
- Age-adjusted thyrotropin criteria for neonatal screening for hypothyroidismThe Journal of Pediatrics, 1990
- Normal ranges of T4 screening values in low birthweight infants.Archives of Disease in Childhood, 1983
- Serum thyrotropin, prolactin, and growth hormone levels during the early neonatal period in the human infantThe Journal of Pediatrics, 1976