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© 2010 American Association for Clinical Chemistry, Inc.
Special Reports |
Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 1: Thyroid-Stimulating Hormone
1 Laboratory for Analytical Chemistry, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium; 2 Department of Clinical Biochemistry, Royal Infirmary, Glasgow, UK; 3 Stanford Medical School, Palo Alto, CA; 4 Department of Clinical Laboratory Medicine, Dokkyo University School of Medicine, Mibu, Tochigi, Japan; 5 Department of Pathology, Virginia Commonwealth University, Richmond, VA; 6 Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA; 7 Laboratoire de Neurobiologie, Centre National de la Recherche Scientifique, Marseille, France; 8 Department of Chemical Endocrinology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; 9 Laboratory of Endocrinology, University Medical Center Utrecht, Utrecht, The Netherlands; 10 Institute for Reference Materials and Measurements (IRMM), Joint Research Centre, European Commission, Geel, Belgium.
aAddress correspondence to this author at: Harelbekestraat 72, B-9000 Gent, Belgium. E-mail: Linda.thienpont{at}ugent.be.
Background: Laboratory testing of serum thyroid-stimulating hormone (TSH) is an essential tool for the diagnosis and management of various thyroid disorders whose collective prevalence lies between 4% and 8%. However, between-assay discrepancies in TSH results limit the application of clinical practice guidelines.
Methods: We performed a method comparison study with 40 sera to assess the result comparability and performance attributes of 16 immunoassays.
Results: Thirteen of 16 assays gave mean results within 10% of the overall mean. The difference between the most extreme means was 39%. Assay-specific biases could be eliminated by recalibration to the overall mean. After recalibration of singlicate results, all assays showed results within the biological total error goal (22.8%), except for 1 result in each of 4 assays. For a sample with a TSH concentration of 0.016 mIU/L, 6 assays either did not report results or demonstrated CVs >20%. Within-run and total imprecision ranged from 1.5% to 5.5% and 2.5% to 7.7%, respectively. Most assays were able to match the internal QC targets within 5%. Within-run drifts and shifts were observed.
Conclusions: Harmonization of TSH measurements would be particularly beneficial for 3 of the 16 examined assays. These data demonstrate that harmonization may be accomplished by establishing calibration traceability to the overall mean values for a panel of patient samples. However, the full impact of the approach must be further explored with a wider range of samples. Although a majority of assays showed excellent quality of performance, some would benefit from improved within-run stability.
The following articles in journals at HighWire Press have cited this article:
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  G. G. Klee Harmonization and Standardization of Thyroid Function Tests Clin. Chem., June 1, 2010; 56(6): 879 - 880. [Full Text] [PDF]
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L. M. Thienpont, K. Van Uytfanghe, G. Beastall, J. D. Faix, T. Ieiri, W. G. Miller, J. C. Nelson, C. Ronin, H. A. Ross, J. H. Thijssen, et al. Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 3: Total Thyroxine and Total Triiodothyronine Clin. Chem., June 1, 2010; 56(6): 921 - 929. [Abstract] [Full Text] [PDF]
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