Resumo

VALENZUELA, Adriana et al. The Reference Value of Thyroid Stimulating Hormone (TSH) Determined by Fluoroimmunoassay in Paraguayan Newborns. Pediatr. (Asunción) [online]. 2011, vol.38, n.2, pp.101-104. ISSN 1683-9803.

The term “reference values" ​​is widely accepted and applied internationally and can be expressed as the establishment and use of data relevant to the interpretation of medical observations. Thyroid stimulating hormone (TSH) plays a role in early detection of one of the few preventable causes of mental retardation, congenital hypothyroidism. The reference values ​​used in the program for prevention of cystic fibrosis and mental retardation (PPFQRM) were those recommended by the commercial test used (<9 Normal, 9-18 borderline, >18 μU/mL hypothyroidism) using filter paper with blood samples from newborns at 2-6 days of life. We performed a cross-sectional, observational study with 20,168 dried blood samples from full-term newborns at 1-7 days of life to determine the reference value for TSH in the NB population of Paraguay using the measures of central tendency and dispersion: mean, median, percentiles, and frequency distribution in order to describe the variable under study. A TSH of between 0.01--1.0 µU/ml was found in 22% of samples, 1.1-2 µU/ml in 25% of samples, from 2.1--3.0 µU/ml in 19%, between 3.1-4 µU/ml in 12%, from 4.1-5 µU/ml in 8%,  and more than 5 µU/ml in 14%. TSH values ​​found were: mean: 2.74, median: 2.22, mode: 0.01, and standard deviation was 2.14 µU/ml. For the 75th percentile: 3.26 µU/ml; 95th: 6.68 µU/ml; and 99th: 9 µU/ml. Based on these observations a cutoff point for TSH was confirmed equivalent to 10 µU/ml.

Palavras-chave : Congenital hypothyroidism; reference values; newborn; thyroid stimulating hormone.

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