Falsely undetectable TSH in a euthyroid patient

Rahimkhani, Monireh; Kazemian, Kiana; daryasari, R Ramezani

doi:10.1186/s13044-020-0076-y

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…There are many comparison methods between different assay systems, but EP9-A2 is the classic and reliable comparison method. 10 , 11 Therefore, in the present study, the EP9-A2 was used to compare with the Jet-iStar 3000 immunoassay analyzer to provide reliable, accurate, and consistent results for clinical practice.…”

Section: Discussionmentioning

confidence: 99%

The Application of the EP9-A Protocol in the Analysis of the Performance of the Immunofluorescence Assay for HCG Detection

Huang¹,

Fu²,

Lv³

et al. 2021

IJGM

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Objective The present study aims to evaluate the comparability of the results of two methodologies for detecting human chorionic gonadotropin (HCG) to assess whether the immunofluorescence method for detecting HCG is adequate for clinical applications. Methods Referring to the protocol requirements of the American Clinical Laboratory Standards Institute (CLSI) EP9-A2 (methodological matching and bias assessment with patient samples), we collected 40 fresh serum specimens from our outpatients and inpatients, including 20 specimens with abnormal HCG concentrations (eight samples with different concentration ranges were selected daily and HCG was measured simultaneously with the two testing systems for five consecutive days). The assays were performed on a Dxl 800 fully automated immunoassay analyzer from Beckman Coulter Inc., USA, as a comparative method and on a Jet-iStar 3000 immunoassay analyzer from Zhonghan Shengtai Inc. as an experimental method. Methodological comparison and bias assessment of the results of the two methods for HCG detection were performed. The OLR regression model was used for calculating bias and regression analysis, and Spearman’s rank correlation coefficient was used for correlation analysis. The correlation and comparability of the two systems were calculated based on the results of the analysis. Results A good correlation in HCG results in the range of 5–50,000 U/mL was obtained from the two assay systems (r = 0.998) with the regression equation of y = 1.020x + 12.96. The estimated deviation was within the permissible deviation and acceptable. Conclusion The results of HCG measurement by the two different assay systems were well correlated and comparable.

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Section: Discussionmentioning

confidence: 99%

The Application of the EP9-A Protocol in the Analysis of the Performance of the Immunofluorescence Assay for HCG Detection

Huang¹,

Fu²,

Lv³

et al. 2021

IJGM

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“…Using these detection platforms, TSH could not be detected in R75G homozygotes, and heterozygotes have been reported to have reduced TSH levels within the reference range. The R75G variant has been reported to be prevalent in individuals of South Asian ethnicity ( 2 ) including Pakistan and India ( 3 ).…”

Section: Introductionmentioning

confidence: 99%

TSHB R75G is a founder variant and prevalent cause of low or undetectable TSH in Indian Jews

Shaki

Eskin‐Schwartz

Hadar

et al. 2022

European Thyroid Journal

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Objective: Bi-allelic loss-of-function mutations in TSHB, encoding the beta-subunit of TSH, cause congenital non-goiterous hypothyroidism. Homozygosity for the TSHB p.R75G variant, previously described in South Asian individuals, does not alter TSH function, but abrogates its detection by some immune-detection-based platforms, leading to erroneous diagnosis of hyperthyroidism. We set out to identify and determine carrier rate of the p.R75G variant among clinically euthyroid Bene Israel Indian Jews, to examine possible founder origin of this variant worldwide and to determine phenotypic effects of its heterozygosity. Design: Molecular genetic studies of Bene Israel Jews and comparative studies with South Asian cohort. Methods: TSHB p.R75G variant tested by Sanger sequencing and RFLP. Haplotype analysis in the vicinity of the TSHB gene performed using SNP arrays. Results: Clinically euthyroid individuals with low or undetectable TSH levels from three apparently unrelated Israeli Jewish families of Bene Israel ethnicity, originating from the Mumbai region of India, were found heterozygous or homozygous for the p.R75G TSHB variant. Extremely high carrier rate of p.R75G TSHB in Bene Israel Indian Jews (~4%) was observed. A haplotype block of 239.7kB in the vicinity of TSHB shared by Bene Israel and individuals of South Asian origin was detected. Conclusions: Our findings highlight the high prevalence of the R75G TSHB variant in euthyroid Bene Israel Indian Jews, demonstrate that heterozygosity of this variant can cause erroneous detection of subnormal TSH levels, and show that R75G TSHB is an ancient founder variant, delineating shared ancestry of its carriers.

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Falsely undetectable TSH in a euthyroid patient

Cited by 2 publications

References 10 publications

The Application of the EP9-A Protocol in the Analysis of the Performance of the Immunofluorescence Assay for HCG Detection

The Application of the EP9-A Protocol in the Analysis of the Performance of the Immunofluorescence Assay for HCG Detection

TSHB R75G is a founder variant and prevalent cause of low or undetectable TSH in Indian Jews

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