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Updated: Jul 6, 2026

Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
Intraindividual variation in serum thyroid hormones, parathyroid hormone and insulin-like growth factor-1
T Ankrah-Tetteh1, S Wijeratne, R Swaminathan
1Department of Chemical Pathology, St Thomas' Hospital, 5th Floor, North Wing, Lambeth Palace Road, London SE1 7EH, UK.
Background:
Biological variation of an analyte is an important determinant of its usefulness. Intraindividual variation in serum thyroid hormones, parathyroid hormone (PTH) and insulin-like growth factor-1 (IGF-1) in healthy subjects was determined in this study.
Methods:
Blood samples were taken at weekly intervals for six weeks from 10 healthy subjects and analysed for serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), PTH and IGF-1.
Results:
Intraindividual variations for serum FT4 and FT3 were <5.0%, IGF-1 9.4% and TSH and PTH 25.1% and 25.9%, respectively. Index of individuality was lowest for FT4 (0.42) and FT3 (0.38), and highest for PTH (1.09).
Conclusion:
Intraindividual variation for FT4, FT3 and IGF-1 are low.
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