OBJECTIVE: Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose @entity1374 in pediatric @entity1 , reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy @entity1 is particularly challenging for pediatric populations. The objective of this study was to determine non-parametric RIs for free @entity1955 (fT4) and free @entity1954 (fT3) using equilibrium dialysis-high performance liquid chromatography-tandem mass spectrometry with over 2200 healthy @entity1 6 months-17 years of age. METHODS: Subjects were negative for both @entity3745 and thyroid peroxidase autoantibodies and had normal thyrotropin concentrations. The study included 2213 @entity1 (1129 @entity1 and 1084 @entity1 ), with at least 120 subjects (average of 125) from each year of life, except for the 6 month to 1 year age group (n=96). RESULTS: Non-parametric RIs (95th percentile) for fT4 were: 18.0-34.7 pmol/L ( @entity1 and @entity1 , 6 months-6 years) and 14.2-25.7 pmol/L ( @entity1 and @entity1 , 7-17 years). RIs for fT3 were: 5.8-13.1 pmol/L ( @entity1 , 6 months-6 years); 5.7-11.8 pmol/L ( @entity1 , 6 months-6 years); 5.7-10.0 pmol/L ( @entity1 and @entity1 , 7-12 years); 4.5-8.6 pmol/L ( @entity1 , 13-17 years); and 5.2-9.4 pmol/L ( @entity1 , 13-17 years). CONCLUSION: Numerous significant differences were observed between pediatric age groups and previously established adult ranges. This emphasizes the need for well-characterized RIs for @entity8789 in the pediatric population.

Pediatric Reference Intervals for Free XXXX and Free @entity1954 by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry.

@entity1 :: ('9606', 'Species') :: ['children', 'patients', 'girls', 'boys'] @entity8789 :: ('MESH:D013963', 'Chemical') :: ['thyroid hormones'] @entity1955 :: ('MESH:D013974', 'Chemical') :: ['thyroxine'] @entity3745 :: ('7038', 'Gene') :: ['thyroglobulin'] @entity1954 :: ('MESH:D014284', 'Chemical') :: ['triiodothyronine'] @entity1374 :: ('MESH:D013959', 'Disease') :: ['thyroid disease']
@entity1955 :: (MESH:D013974,Chemical) :: ['Thyroxine']
