Interlaboratory variability of urinary iodine measurements
-
Till Ittermann
,
Simone Johner
Abstract
Background:
The iodine status of populations is usually assessed by median urinary iodine concentrations (UIC) in population-based studies, but it is unclear to which extent UIC are comparable across different laboratories. The aim of our study was to investigate the variability of UIC measurements across three well-established German laboratories with long-term clinical-chemical expertise in iodine measurements and to compare these results to the gold standard inductively coupled plasma mass spectrometry (ICP-MS).
Methods:
UIC levels were measured from 303 urine samples derived from the “Dortmund Nutritional and Anthropometric Longitudinally Designed Study” and from volunteers of the University Medicine Greifswald at four different German laboratories. Three of these laboratories used Sandell-Kolthoff reaction with different digestion methods for UIC measurement (Lab1–Lab3), whereas one laboratory used ICP-MS as gold standard.
Results:
Median UIC levels were significantly different across the four laboratories (ICP-MS: 77 μg/L; Lab1: 69 μg/L; Lab2: 73 μg/L; Lab3: 111 μg/L). Linear regressions associating UIC levels of Lab1–Lab3 with UIC levels of ICP-MS showed intercepts significantly different from 0 and slopes significantly different from 1. Intraclass correlations (ICC) in comparison to ICP-MS were 0.91 for Lab1, 0.98 for Lab2, and 0.69 for Lab3. Using the digestion method of Lab2 in Lab3 improved the comparison of UIC levels of Lab3 with those from the ICP-MS (ICC=0.89).
Conclusions:
We have demonstrated larger interlaboratory variations across high-quality laboratories with long-lasting experience in iodine measurements indicating a relevant non-comparability of UIC measurements in iodine monitoring studies. Therefore, standardization of UIC measurements has to be expedited.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: This work was supported by EUthyroid. The project has received funding from the European Union’s Horizon 2020 Framework Programme, research and innovation program under grant agreement number 634453.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References
1. World Health Organization. Assessment of iodine deficiency disorders and monitoring their elimination. A guide for programme managers, 3rd ed. Geneva, Switzerland: WHO Press, 2007.Suche in Google Scholar
2. Zimmermann MB, Andersson M. Update on iodine status worldwide. Curr Opin Endocrinol Diabetes Obes 2012;19:382–7.10.1097/MED.0b013e328357271aSuche in Google Scholar PubMed
3. Shelor CP, Dasgupta PK. Review of analytical methods for the quantification of iodine in complex matrices. Anal Chim Acta 2011;702:16–36.10.1016/j.aca.2011.05.039Suche in Google Scholar PubMed
4. Caldwell KL, Maxwell CB, Makhmudov A, Pino S, Braverman LE, Jones RL, et al. Use of inductively coupled plasma mass spectrometry to measure urinary iodine in NHANES 2000: comparison with previous method. Clin Chem 2003;49:1019–21.10.1373/49.6.1019Suche in Google Scholar PubMed
5. EQUIP Program. Available at: http://www.cdc.gov/labstandards/equip.html. Accessed: July 2017.Suche in Google Scholar
6. Buyken AE, Alexy U, Kersting M, Remer T. The DONALD cohort. An updated overview on 25 years of research based on the Dortmund Nutritional and Anthropometric Longitudinally Designed study. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2012;55:875–84.10.1007/s00103-012-1503-6Suche in Google Scholar PubMed
7. Volzke H, Alte D, Schmidt CO, Radke D, Lorbeer R, Friedrich N, et al. Cohort profile: the study of health in Pomerania. Int J Epidemiol 2011;40:294–307.10.1093/ije/dyp394Suche in Google Scholar PubMed
8. Remer T, Montenegro-Bethancourt G, Shi L. Long-term urine biobanking: storage stability of clinical chemical parameters under moderate freezing conditions without use of preservatives. Clin Biochem 2014;47:307–11.10.1016/j.clinbiochem.2014.09.009Suche in Google Scholar PubMed
9. Leiterer M, Truckenbrodt D, Franke K. Determination of iodine species in milk using ion chromatographic separation and ICP-MS detection. Eur Food Res Technol 2001;213:150–3.10.1007/s002170100333Suche in Google Scholar
10. Benotti J, Benotti N, Pino S, Gardyna H. Determination of total iodine in urine, stool, diets, and tissue. Clin Chem 1965;11:932–6.10.1093/clinchem/11.10.932Suche in Google Scholar
11. Pino S, Fang SL, Braverman LE. Ammonium persulfate: a safe alternative oxidizing reagent for measuring urinary iodine. Clin Chem 1996;42:239–43.10.1093/clinchem/42.2.239Suche in Google Scholar
12. Zimmermann MB, Aeberli I, Andersson M, Assey V, Yorg JA, Jooste P, et al. Thyroglobulin is a sensitive measure of both deficient and excess iodine intakes in children and indicates no adverse effects on thyroid function in the UIC range of 100–299 mug/L: a UNICEF/ICCIDD study group report. J Clin Endocrinol Metab 2013;98:1271–80.10.1210/jc.2012-3952Suche in Google Scholar PubMed
13. Spencer CA, Takeuchi M, Kazarosyan M, Wang CC, Guttler RB, Singer PA, et al. Serum thyroglobulin autoantibodies: prevalence, influence on serum thyroglobulin measurement, and prognostic significance in patients with differentiated thyroid carcinoma. J Clin Endocrinol Metab 1998;83:1121–7.10.1210/jc.83.4.1121Suche in Google Scholar
14. Shan Z, Chen L, Lian X, Liu C, Shi B, Shi L, et al. Iodine status and prevalence of thyroid disorders after introduction of mandatory universal salt iodization for 16 years in china: a cross-sectional study in 10 cities. Thyroid 2016;26:1125–30.10.1089/thy.2015.0613Suche in Google Scholar PubMed
15. Koukkou E, Ilias I, Mamalis I, Adonakis GG, Markou KB. Serum thyroglobulin concentration is a weak marker of iodine status in a pregnant population with iodine deficiency. Eur Thyroid J 2016;5:120–4.10.1159/000446070Suche in Google Scholar PubMed PubMed Central
©2018 Walter de Gruyter GmbH, Berlin/Boston
Artikel in diesem Heft
- Frontmatter
- Editorial
- Analytical quality: an unfinished journey
- Reviews
- Update in diagnosis and management of primary aldosteronism
- Diagnosis biomarkers in acute intestinal ischemic injury: so close, yet so far
- Opinion Papers
- Irregular analytical errors in diagnostic testing – a novel concept
- A Black Swan in clinical laboratory practice: the analytical error due to interferences in immunoassay methods
- General Clinical Chemistry and Laboratory Medicine
- Reaching consensus on communication of critical laboratory results using a collective intelligence method
- Stability of routine biochemical analytes in whole blood and plasma/serum: focus on potassium stability from lithium heparin
- GFR estimation based on standardized creatinine and cystatin C: a European multicenter analysis in older adults
- Binding of bromocresol green and bromocresol purple to albumin in hemodialysis patients
- Interlaboratory variability of urinary iodine measurements
- The venous thromboembolic risk and the clot wave analysis: a useful relationship?
- Hematology and Coagulation
- Autovalidation and automation of the postanalytical phase of routine hematology and coagulation analyses in a university hospital laboratory
- Reference Values and Biological Variations
- Indirect method for validating transference of reference intervals
- Differences in levels of albumin, ALT, AST, γ-GT and creatinine in frail, moderately healthy and healthy elderly individuals
- Cancer Diagnostics
- Serum exosomal hnRNPH1 mRNA as a novel marker for hepatocellular carcinoma
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Artikel in diesem Heft
- Frontmatter
- Editorial
- Analytical quality: an unfinished journey
- Reviews
- Update in diagnosis and management of primary aldosteronism
- Diagnosis biomarkers in acute intestinal ischemic injury: so close, yet so far
- Opinion Papers
- Irregular analytical errors in diagnostic testing – a novel concept
- A Black Swan in clinical laboratory practice: the analytical error due to interferences in immunoassay methods
- General Clinical Chemistry and Laboratory Medicine
- Reaching consensus on communication of critical laboratory results using a collective intelligence method
- Stability of routine biochemical analytes in whole blood and plasma/serum: focus on potassium stability from lithium heparin
- GFR estimation based on standardized creatinine and cystatin C: a European multicenter analysis in older adults
- Binding of bromocresol green and bromocresol purple to albumin in hemodialysis patients
- Interlaboratory variability of urinary iodine measurements
- The venous thromboembolic risk and the clot wave analysis: a useful relationship?
- Hematology and Coagulation
- Autovalidation and automation of the postanalytical phase of routine hematology and coagulation analyses in a university hospital laboratory
- Reference Values and Biological Variations
- Indirect method for validating transference of reference intervals
- Differences in levels of albumin, ALT, AST, γ-GT and creatinine in frail, moderately healthy and healthy elderly individuals
- Cancer Diagnostics
- Serum exosomal hnRNPH1 mRNA as a novel marker for hepatocellular carcinoma
- Intragenic hypomethylation of DNMT3A in patients with myelodysplastic syndrome
- Cardiovascular Diseases
- Evaluation of analytical performance of a new high-sensitivity immunoassay for cardiac troponin I
- MEF2C loss-of-function mutation associated with familial dilated cardiomyopathy
- Letter to the Editor
- Hyperuricemia does not seem to be an independent risk factor for coronary heart disease
- Reply to: Hyperuricemia does not seem to be an independent risk factor for coronary heart disease
- Preanalytics of ammonia: stability, transport and temperature of centrifugation
- Influence of delayed separation of plasma from whole blood on Cu, I, Mn, Se, and Zn plasma concentrations
- Copeptin as a diagnostic and prognostic biomarker in patients admitted to Emergency Department with syncope, presyncope and vertiginous syndrome
- Development of an internally controlled quantitative PCR to measure total cell-associated HIV-1 DNA in blood
- Selective changes in cholesterol metabolite levels in plasma of breast cancer patients after tumor removal
- Athletes beware before throwing towels to audiences
