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Croatian Medical Journal, Vol. 51 No. 2, 2010.

Original scientific paper

Indirect Reference Intervals Estimated from Hospitalized Population for Thyrotropin and Free Thyroxine

Tamer C. Inal ; Department of Biochemistry, Acibadem University, School of Medicine, Istanbul, Turkey
Mustafa Serteser ; Department of Biochemistry, Acibadem University, School of Medicine, Istanbul, Turkey
Abdurrahman Coşkun ; Department of Biochemistry, Acibadem University, School of Medicine, Istanbul, Turkey
Aysel Özpinar ; Department of Biochemistry, Acibadem University, School of Medicine, Istanbul, Turkey
Ibrahim Ünsal ; Department of Biochemistry, Acibadem University, School of Medicine, Istanbul, Turkey

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Abstract

Aim To establish indirect reference intervals from patient
results obtained during routine laboratory work as an alternative
to laborious and expensive producing of their own
reference range values according to international instructions.
Methods All results for thyrotropin (TSH) and free thyroxine
(T4) that were stored in our laboratory information system
between 2004 and 2008 were included in this study.
After a logarithmic transformation of the raw data, outliers
were excluded. Non-parametric reference intervals were
estimated statistically after visual observation of the distribution
using stem-and-leaf plots and histograms. A standard
normal deviation test was performed to test the significance
of differences between sub-groups.
Results There was no significant difference in serum TSH
or free T4 concentrations between male and female participants.
Because no differences were found within the time
span of the study, combined reference intervals were calculated.
Indirect reference values were 0.43-3.93 mU/L for
TSH and 11.98-21.33 pmol/L for free T4.
Conclusion Using patient laboratory data values is a relatively
easy and cheap method of establishing laboratoryspecific
reference values if skewness and kurtosis of the
distribution are not too large.

Keywords

patient data; laboratory information system; thyroid function test

Hrčak ID:

53514

URI

https://hrcak.srce.hr/53514

Publication date:

15.4.2010.

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