Age-specific thyroid hormone and thyrotropin reference intervals for a pediatric and adolescent population
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Eduardo A. Chaler
, Romina Fiorenzano
Abstract
Background: Establishment of reliable reference intervals remains valuable for confirming validity and advancing standardization across methods and populations. Moreover, knowledge of the measurement uncertainty (U) and of the reference change value (RCV) has important applications in clinical chemistry.
Methods: Starting from the information available in the laboratory data base (29,901 subjects) an initial selection was carried out by eliminating all subjects with a clinical or laboratory pathological report; data from 7581 0- to 20-year-old subjects (53.87% girls) remained in the study. These subjects, divided into nine age groups, were used to define reference distribution percentiles (2.5th, 50th and 97.5th) of serum thyrotropin (TSH), triiodothyronine (T3), thyroxine (T4), and free T4 (fT4), as well as U and RCV of these assays.
Results: In early infancy, T4 and fT4 values were higher than in the older age groups. Serum T4 95th percentile reference value, useful for the diagnosis of hyperthyroidism, was 142.9 in 20-year-old boys and 230.4 nmol/L in early infants and serum T3 95th percentile was 2.6 and 3.5 nmol/L, respectively, while fT4 2.5th percentile reference value, useful for the diagnosis of hypothyroidism, was 9.6 and 13.0 pmol/L, respectively. Serum TSH 97.5th percentile showed less age variation, 4.38–4.88 mIU/L. Performance of the four assays resulted in approximately 20% Us, reflecting simple and complex imprecision, trueness, analytical and functional sensitivity. RCV of serum TSH (58.6%) was larger than for thyroid hormones (28.3%–34.7%), probably due to the high biological variation of this hormone.
Conclusions: We have established reference interval for TSH and thyroid hormones, as well as Us for assessing reliability of measurements, and RCVs to alert users on the presence of clinical significant changes.
©2012 by Walter de Gruyter Berlin Boston
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Articles in the same Issue
- Masthead
- Masthead
- Editorials
- Reference values and the journal: why the past is now present
- Other-than-annual variations in morning determinations of uric acid
- Reviews
- Blood biochemical markers of bone turnover: pre-analytical and technical aspects of sample collection and handling
- A comprehensive review of upper reference limits reported for (high-)sensitivity cardiac troponin assays: the challenges that lie ahead
- Mini Review
- Reference change values
- Opinion Papers
- Obtaining reference intervals traceable to reference measurement systems: is it possible, who is responsible, what is the strategy?
- Analytical performance, reference values and decision limits. A need to differentiate between reference intervals and decision limits and to define analytical quality specifications
- A pragmatic proposal for permissible limits in external quality assessment schemes with a compromise between biological variation and the state of the art
- Original Articles
- Age dependence of within-subject biological variation of nine common clinical chemistry analytes
- Population-based pediatric reference intervals for general clinical chemistry analytes on the Abbott Architect ci8200 instrument
- Uric acid biorhythm, a feature of long-term variation in a clinical laboratory database
- Age-related changes in serum amino acids concentrations in healthy individuals
- Characterisation of a highly sensitive troponin I assay and its application to a cardio-healthy population
- Are the currently used reference intervals for creatine kinase (CK) reflecting the general population? The Tromsø Study
- Age-specific thyroid hormone and thyrotropin reference intervals for a pediatric and adolescent population
- Serum thyroglobulin reference values according to NACB criteria in healthy subjects with normal thyroid ultrasound
- Thyroid volume influences serum calcitonin levels in a thyroid-healthy population: results of a 3-assay, 519 subjects study
- Impact of the reference values on the clinically-relevant cut-offs. The example of cortisol testing in children
- Trimester-specific reference intervals for haemoglobin A1c (HbA1c) in pregnancy
- The concentration of adiponectin in breast milk is related to maternal hormonal and inflammatory status during 6 months of lactation
- Age- and sex-specific reference limits for creatinine, cystatin C and the estimated glomerular filtration rate
- Determination of the biological variation of S100β and lactate dehydrogenase in disease-free patients with malignant melanoma
- Reference intervals and biological variation for kallikrein 6: influence of age and renal failure
- Faecal haemoglobin concentrations by gender and age: implications for population-based screening for colorectal cancer
- Reference intervals of extended erythrocyte and reticulocyte parameters
- Haematological and iron metabolism parameters in professional cyclists during the Giro d’Italia 3-weeks stage race
- Reference change values for lens culinaris agglutinin-reactive α-fetoprotein and des-γ-carboxy prothrombin in patients with chronic hepatitis C
- Letters to the Editor
- Disadvantages of using biological variation data for reference change values
- Reference change values may need some improvement but are invaluable tools in laboratory medicine
- Insulin-like growth factor 1 reference intervals for a chemiluminescent enzyme immunometric assay (Immulite 2000®) in an adult Mediterranean population
- Reference values for new red blood cell and platelet parameters on the Abbott Diagnostics Cell-Dyn Sapphire
- Congress Abstracts
- Swiss MedLab 2012 Congress of the Swiss Union of Laboratory Medicine (SULM)