scholarly journals Harmonization of Serum Thyroid-Stimulating Hormone Measurements Paves the Way for the Adoption of a More Uniform Reference Interval

2017 ◽  
Vol 63 (7) ◽  
pp. 1248-1260 ◽  
Author(s):  
Linda M Thienpont ◽  
Katleen Van Uytfanghe ◽  
Linde A C De Grande ◽  
Dries Reynders ◽  
Barnali Das ◽  
...  
Keyword(s):  
Total Error ◽  
Method Comparison ◽  
Reference Interval ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Nonparametric Bootstrap ◽  
Serum Samples ◽  
Global Harmonization ◽  
Method Comparison Study ◽  
Stimulating Hormone

Abstract BACKGROUND The IFCC Committee for Standardization of Thyroid Function Tests developed a global harmonization approach for thyroid-stimulating hormone measurements. It is based on a multiassay method comparison study with clinical serum samples and target setting with a robust factor analysis method. Here we describe the Phase IV method comparison and reference interval (RI) studies conducted with the objective to recalibrate the participating assays and demonstrate the proof-of-concept. METHODS Fourteen manufacturers measured the harmonization and RI panel; 4 of them quantified the harmonization and first follow-up panel in parallel. All recalibrated their assays to the statistically inferred targets. For validation, we used desirable specifications from the biological variation for the bias and total error (TE). The RI measurements were done with the assays' current calibrators, but data were also reported after transformation to the new calibration status. We estimated the pre- and postrecalibration RIs with a nonparametric bootstrap procedure. RESULTS After recalibration, 14 of 15 assays met the bias specification with 95% confidence; 8 assays complied with the TE specification. The CV of the assay means for the harmonization panel was reduced from 9.5% to 4.2%. The RI study showed improved uniformity after recalibration: the ranges (i.e., maximum differences) exhibited by the assay-specific 2.5th, 50th, and 97.5th percentile estimates were reduced from 0.27, 0.89, and 2.13 mIU/L to 0.12, 0.29, and 0.77 mIU/L. CONCLUSIONS We showed that harmonization increased the agreement of results from the participating immunoassays, and may allow them to adopt a more uniform RI in the future.

scholarly journals A raised thyroid stimulating hormone result - a 12-month follow-up study in general practice

2010 ◽  
Vol 2 (1) ◽  
pp. 29 ◽  
Author(s):  
Veronique Gibbons ◽  
John Conaglen ◽  
Ross Lawrenson
Keyword(s):  
General Practice ◽  
Quantitative Research ◽  
Best Practice ◽  
Adult Population ◽  
Laboratory Data ◽  
Reference Interval ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Stimulating Hormone

INTRODUCTION: Subclinical hypothyroidism (SCH) is common in older patients. AIM: To review the management of patients identified with a raised thyroid stimulating hormone (TSH) result in a 12-month period and compare this to current guidelines from the New Zealand Best Practice Advocacy Centre (BPAC). METHODS: We collected laboratory data on thyroid function tests (TFTs) that were reported between December 2005 and November 2006 from two general practices with an adult population of approximately 21 000. Data were collected on symptoms, investigations, thyroid medication, family history and comorbidities. We used chi-squared tests to compare findings by age, gender and ethnicity. RESULTS: Older women of European descent were more likely to be to have initial results suggesting SCH. The number of follow-up tests ranged from 0 to 5 tests in a 12-month period. Forty-eight percent of individuals did not have any follow-up investigations. Seventy-three percent of FT4 tests taken are requested concurrently with TSH. Of those who had a repeat TSH test, just over 40% had a result within the reference interval. Twenty-eight percent had two TSH results consistent with SCH. Thirty-five percent of patients with antibody results were positive. The most commonly-recorded symptoms were tiredness and weight gain. DISCUSSION: We found inconsistencies in the management of SCH which were not related to patient characteristics such as age, gender or ethnicity. Further research is needed to determine if SCH is associated with increased morbidity and to provide a clear rationale for management of patients with SCH. KEYWORDS: Hypothyroidism; family practice; quantitative research; general practice

scholarly journals Performance Characteristics of Six Third-Generation Assays for Thyroid-Stimulating Hormone

2004 ◽  
Vol 50 (12) ◽  
pp. 2338-2344 ◽  
Author(s):  
Mindy L Rawlins ◽  
William L Roberts
Keyword(s):  
Method Comparison ◽  
Measurement Range ◽  
Thyroid Stimulating Hormone ◽  
Performance Characteristics ◽  
Third Generation ◽  
Serum Samples ◽  
Current Guidelines ◽  
Automated Methods ◽  
Stimulating Hormone

Abstract Background: Thyroid-stimulating hormone (TSH) is used to detect primary hypo- and hyperthyroidism. Current guidelines for TSH assays recommend a functional sensitivity of ≤0.02 mIU/L. The protocol for determining the functional sensitivity of TSH assays specifies analyses of serum samples with two reagent lots over a 6- to 8-week period. Methods: We determined the functional sensitivities of the Access 2, ADVIA Centaur, ARCHITECT i2000, E170, IMMULITE 2000, and Vitros ECi automated methods, using seven serum pools and two reagent lots for each method. Results: The observed functional sensitivities were as follows: Access 2, <0.020 mIU/L; ADVIA Centaur, 0.039 mIU/L; ARCHITECT i2000, <0.005 mIU/L; Elecsys E170, 0.011 mIU/L; IMMULITE 2000, 0.014 mIU/L; Vitros ECi, 0.004 mIU/L. However, there were large differences between some method means for the seven serum pools. For the pool with the lowest TSH concentration, mean results were as follows: Access 2, 0.0203 mIU/L; ADVIA Centaur, 0.0085 mIU/L; ARCHITECT i2000, 0.0049 mIU/L; E170, 0.0098 mIU/L; IMMULITE 2000, 0.0077 mIU/L; Vitros ECi, 0.0014 mIU/L. Method-comparison studies using samples with TSH concentrations >0.2 mIU/L also showed method differences. The ARCHITECT i2000 method was the most precise at low TSH concentrations. Conclusions: TSH methods do not provide comparable results for serum pools with TSH concentrations <0.2 mIU/L or for patient results across the analytic measurement range. Further investigation into the cause of these differences and additional harmonization efforts are required.

Comparison of in-clinic point-of-care and reference laboratory total thyroxine immunoassays for diagnosis and post-treatment monitoring of hyperthyroid cats

2017 ◽  
Vol 20 (4) ◽  
pp. 319-324 ◽  
Author(s):  
Mark E Peterson ◽  
Mark Rishniw ◽  
Graham E Bilbrough ◽  
Kate B Cote
Keyword(s):  
Point Of Care ◽  
Method Comparison ◽  
Reference Interval ◽  
Thyroid Stimulating Hormone ◽  
Reference Laboratory ◽  
Good Precision ◽  
Serum Samples ◽  
Free T4 ◽  
Total Thyroxine ◽  
Assay Precision

Objectives The Catalyst One Chemistry Analyzer (IDEXX Laboratories) is a point-of-care instrument that can measure total thyroxine (TT4) by immunoassay. The aims of this study were to evaluate the analytic performance of the Catalyst TT4 assay in feline sera and to examine agreement of the Catalyst TT4 results with those measured by immunoassay at a veterinary reference laboratory. Methods Assay precision, reproducibility and linearity were evaluated for the Catalyst TT4 assay. For method comparison, TT4 concentrations in serum samples from 157 cats (127 hyperthyroid, 30 radioiodine-treated cats) were analyzed by both in-clinic and reference laboratory methods. Results The Catalyst TT4 demonstrated good precision and reproducibility (coefficients of variation ⩽8.5%) and excellent linearity in the diagnostic range of 6–150 nmol/l. Differences between the two TT4 methods showed no proportional or fixed bias (Bland–Altman plots) but did demonstrate greater spread of values at higher TT4 concentrations. Statistical analysis of percent differences between methods indicated 95% limits of agreement of ± 30%. When serum TT4 concentrations were classified as low, high or within the reference interval (12–50 nmol/l) for each assay, there was strong agreement (96.8%) in classification between methods. Conclusions and relevance The Catalyst TT4 assay provided precise serum TT4 concentrations in the 157 samples analyzed, which agreed well with results provided by a reference laboratory. Cats with Catalyst TT4 concentrations near decision thresholds (eg, normal vs high) should either have TT4 concentration repeated a few weeks later and/or undergo further testing (eg, free T4, serum thyroid-stimulating hormone, thyroid scintigraphy) to determine thyroid status.

scholarly journals Management of thyroid disease in pregnancy – Room for improvement in the first trimester

2016 ◽  
Vol 9 (3) ◽  
pp. 126-129 ◽  
Author(s):  
Helen Robinson ◽  
Philip Robinson ◽  
Michael D’Emden ◽  
Kassam Mahomed
Keyword(s):  
General Practitioner ◽  
Thyroid Function ◽  
Thyroid Disease ◽  
Thyroid Dysfunction ◽  
First Trimester ◽  
Antenatal Clinic ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
In Pregnancy ◽  
Stimulating Hormone

Background First-trimester care of maternal thyroid dysfunction has previously been shown to be poor. This study evaluates early management of thyroid dysfunction in pregnancy in Australia. Methods Patients reviewed by the Obstetric Medicine team for thyroid dysfunction from 1 January 2012 to 30 June 2013 were included. Data were collected on gestation at referral from the patient’s general practitioner to the antenatal clinic, information provided in the referral letter, thyroid function tests and thyroid medications. Results Eighty-five women were included in the study. At the time of general practitioner referral to antenatal services, 19% of women with preexisting thyroid disease had no thyroid function tested. Forty-three percent had an abnormal thyroid-stimulating hormone defined as being outside the laboratory-specific pregnancy reference range if available, or outside the level of 0.1–2.5 mIu/L in the first trimester, 0.2–3.0 mIu/L in the second trimester and 0.3–3.0 mIu/L in the third trimester. Only 21% of women increased their thyroxine dose prior to their first antenatal clinic review. Conclusion This study highlights that a significant proportion of women with known thyroid disease either have untested thyroid function in the first trimester or a thyroid-stimulating hormone outside of levels recommended by guidelines.

scholarly journals Verification study of free light chains assays on reagent-optimized analysers

2019 ◽  
Vol 29 (3) ◽  
pp. 579-586
Author(s):  
Dragana Šegulja ◽  
Danica Matišić ◽  
Karmela Barišić ◽  
Dunja Rogić
Keyword(s):  
Method Comparison ◽  
Correlation Coefficients ◽  
Light Chains ◽  
Free Light Chains ◽  
Serum Samples ◽  
Three Samples ◽  
Coefficients Of Variation ◽  
Satisfactory Precision ◽  
Haematological Patients ◽  
Method Comparison Study

Introduction: Our aim was to compare analytical specifications of two assays (monoclonal vs. polyclonal) for free light chains (FLCs) quantification optimized for two different analytical platforms, nephelometer ProSpec (Siemens, Erlangen, Germany) and turbidimetric analyser Optilite (The Binding Site, Birmingham, UK). Materials and methods: The evaluation included verification of the precision, repeatability and reproducibility, estimation of accuracy and method comparison study with 37 serum samples of haematological patients. Kappa and lambda FLC were measured in each sample by both methods and kappa/lambda ratio was calculated. Results: Results show satisfactory precision of both methods with coefficients of variation for ProSpec of CVwr = 2.20% and CVbr = 3.44%, and for Optilite CVwr = 2.82% and CVbr = 4.15%. Estimated bias for FLC lambda was higher on the ProSpec analyser, but bias for FLC kappa was higher on the Optilite analyser. Correlation coefficients were 0.98; P < 0.001 for FLC kappa and 0.97; P < 0.001 for FLC lambda. Considering normal/pathological FLC ratio moderate agreement within assays was detected (κ = 0.621). When the results were categorized according to criteria for progressive disease, 4/37 (0.10) cases were differently classified. Lambda FLC values by Optilite in three samples with monoclonal FLC lambda were more than twelve times higher than by ProSpec. A 25% difference in FLC ratio was detected in 16/37 (0.43) and 50% difference in 13/37 (0.35) patients. Conclusions: All manufacturers’ precision claims could not be achieved in the verification study. The comparison of results to biological variations data showed that coefficients of variations are acceptable for both assays. The assays should not be used interchangeably in haematological patients.

scholarly journals In primary care, is measuring free-thyroxine plus thyroid-stimulating hormone to detect hypopituitarism cost-effective? A cost utility analysis using Markov chain models

BMJ Open ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. e029369 ◽  
Author(s):  
Brian Shine ◽  
Tim James ◽  
Amanda Adler
Keyword(s):  
Primary Care ◽  
Model Simulation ◽  
Cost Effective ◽  
Cost Utility ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Life Years ◽  
Secondary Hypothyroidism ◽  
Stimulating Hormone

ObjectiveWe examined whether it is cost-effective to measure free thyroxine (FT4) in addition to thyrotropin (thyroid-stimulating hormone (TSH)) on all requests for thyroid function tests from primary care on adult patients.BackgroundHypopituitarism occurs in about 4 people per 100 000 per year. Loss of thyrotropin (TSH) secretion may lead to secondary hypothyroidism with a low TSH and low FT4, and this pattern may help to diagnose hypopituitarism that might otherwise be missed.DesignMarkov model simulation.Primary outcome measureIncremental cost-effectiveness ratio (ICER), the ratio of cost in pounds to benefit in quality-adjusted life years of this strategy.ResultsThe ICER for this strategy was £71 437. Factors with a large influence on the ICER were the utilities of the treated hypopituitary state, the likelihood of going to the general practitioner (GP) and of the GP recognising a hypopituitary patient. The ICER would be below £20 000 at a cost to the user of an FT4 measurement of £0.61.ConclusionWith FT4 measurements at their present cost to the user, routine inclusion of FT4 in a thyroid hormone profile is not cost-effective.

scholarly journals How well does the capillary thyroid-stimulating hormone test for newborn thyroid screening predict the venous free thyroxine level?

2016 ◽  
Vol 101 (6) ◽  
pp. 539-545 ◽  
Author(s):  
Tzveta Pokrovska ◽  
Jeremy Jones ◽  
M Guftar Shaikh ◽  
Sarah Smith ◽  
Malcolm D C Donaldson
Keyword(s):  
Newborn Infants ◽  
Rank Correlation ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Spearman’S Rank Correlation ◽  
Thyroid Screening ◽  
Spearman’S Rank Correlation Coefficient ◽  
Venous Sample ◽  
Stimulating Hormone

ObjectivesTo determine, in newborn infants referred with elevated capillary thyroid-stimulating hormone (TSH), a threshold below which a frankly subnormal venous free thyroxine (fT4) level of <10 pmol/L is unlikely, so that treatment with levo-thyroxine (L-T4) might be deferred until venous thyroid function tests (TFTs) become available.Subjects and methodsAll infants referred in Scotland since 1979 with capillary TSH elevation were studied, with particular focus on infants screened using the AutoDELFIA assay between 2002 and 2013.ResultsOf the 321 infants referred with capillary TSH elevation using AutoDELFIA, 35 were excluded (fT4/TSH unavailable (12), venous sample either preceding or >10 days after capillary sampling (13, 10)), leaving 286 eligible for analysis (208 definite/probable hypothyroidism, 61 transient TSH elevation, 17 of uncertain thyroid status). Capillary TSH and venous T4 were strongly correlated (Spearman's rank correlation coefficient −0.707355). The optimal capillary TSH threshold for predicting a venous fT4 of <10 pmol/L was found to be >40 mU/L (90.3% sensitivity and 65.9% specificity compared with 90.25% and 59.1% for >35 mU/L and 88.3% and 68.2% for >45 mU/L). 93 infants (32.5%) had capillary TSH ≤40 mU/L at referral of whom 15 (9.7%) had venous fT4 <10 pmol/L, comprising seven with true congenital hypothyroidism, five with transient TSH elevation and three with uncertain status, two of whom died.ConclusionFor infants in whom capillary TSH is ≤40 mU/L, it is reasonable to defer L-T4 treatment until venous TFT results are known provided that the latter become available quickly.

scholarly journals Standardization of Free Thyroxine Measurements Allows the Adoption of a More Uniform Reference Interval

2017 ◽  
Vol 63 (10) ◽  
pp. 1642-1652 ◽  
Author(s):  
Linde A C De Grande ◽  
Katleen Van Uytfanghe ◽  
Dries Reynders ◽  
Barnali Das ◽  
James D Faix ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Equilibrium Dialysis ◽  
Total Error ◽  
Reference Interval ◽  
Measurement Procedure ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Proof Of Concept ◽  
Reference Measurement ◽  
Statistical Procedures

Abstract BACKGROUND The IFCC Committee for Standardization of Thyroid Function Tests intended to standardize free thyroxine (FT4) immunoassays. We developed a Système International d'Unités traceable conventional reference measurement procedure (RMP) based on equilibrium dialysis and mass spectrometry. We describe here the latest studies intended to recalibrate against the RMP and supply a proof of concept, which should allow continued standardization efforts. METHODS We used the RMP to target the standardization and reference interval (RI) panels, which were also measured by 13 manufacturers. We validated the suitability of the recalibrated results to meet specifications for bias (3.3%) and total error (8.0%) determined from biological variation. However, because these specifications were stringent, we expanded them to 10% and 13%, respectively. The results for the RI panel were reported as if the assays were recalibrated. We estimated all but 1 RI using parametric statistical procedures and hypothesized that the RI determined by the RMP was suitable for use by the recalibrated assays. RESULTS Twelve of 13 recalibrated assays had a bias, meeting the 10% specification with 95% confidence; for 7 assays, this applied even for the 3.3% specification. Only 1 assay met the 13% total error specification. Recalibration reduced the CV of the assay means for the standardization panel from 13% to 5%. The proof-of-concept study confirmed our hypothesis regarding the RI but within constraints. CONCLUSIONS Recalibration to the RMP significantly reduced the FT4 immunoassays' bias, so that the RI determined by the RMP was suitable for common use within a margin of 12.5%.

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