scholarly journals Correlations of Free Thyroid Hormones Measured by Tandem Mass Spectrometry and Immunoassay with Thyroid-Stimulating Hormone across 4 Patient Populations

2009 ◽  
Vol 55 (7) ◽  
pp. 1380-1388 ◽  
Author(s):  
Jacqueline Jonklaas ◽  
Natasa Kahric-Janicic ◽  
Offie P Soldin ◽  
Steven J Soldin
Keyword(s):  
Mass Spectrometry ◽  
Thyroid Hormone ◽  
Tandem Mass Spectrometry ◽  
Thyroid Hormones ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Tandem Mass ◽  
Free Triiodothyronine ◽  
Free Thyroid Hormones ◽  
Free Thyroid Hormone

Abstract Background: Accurate measurement of free thyroid hormones is important for managing thyroid disorders. Ultrafiltration liquid chromatography tandem mass spectrometry (LC-MS/MS) can reliably measure the concentrations of small molecules, including thyroid hormones. Our study was designed to compare free thyroid hormone measurements performed with immunoassay and LC-MS/MS. Methods: We studied the performance of LC-MS/MS in 4 different populations comprising pediatric patients, euthyroid adults, and healthy nonpregnant and pregnant women. The samples obtained from each population numbered 38, 200, 28, and 128, respectively. Free thyroxine, free triiodothyronine, and thyroid-stimulating hormone (TSH) concentrations were documented. Results: LC-MS/MS measurement of free thyroid hormones provided better correlation with log-transformed serum TSH in each population and also the populations combined. The correlations between free thyroxine measured by LC-MS/MS and log TSH in the pediatric outpatients and healthy adults were −0.90 and −0.77, respectively. The correlations for immunoassay were −0.82 and −0.48. The correlations between free triiodothyronine measured by LC-MS/MS and TSH for both pediatric and healthy adult populations were −0.72 and −0.68, respectively. Conclusions: Free thyroid hormone concentrations measured by LC-MS/MS correlate to a greater degree with log TSH values compared to concentrations measured by immunoassay. This correlation was maintained across the patient populations we studied and may reflect the accuracy and specificity of LC-MS/MS. The superior ability of LC-MS/MS to enable documentation of the well-known thyroid hormone–TSH relationship supports the use of this measurement technique in a variety of clinical situations.

Comparison of calculated and measured free thyroid hormones in serum in health and in abnormal states.

1982 ◽  
Vol 28 (6) ◽  
pp. 1325-1329 ◽  
Author(s):  
G Fresco ◽  
G Curti ◽  
A Biggi ◽  
B Fontana
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pregnant Women ◽  
Healthy Subjects ◽  
Normal Subjects ◽  
Mass Action ◽  
Law Of Mass Action ◽  
Free Triiodothyronine ◽  
Free Thyroid Hormones ◽  
Free Thyroid Hormone

Abstract To evaluate a theoretical model for calculating free thyroid hormones, based on the law of mass action, we compared values for both calculated and measured free thyroxin and free triiodothyronine in a group of normal subjects. To determine whether the concentrations of circulating free hormones were also predictable from equilibrium considerations in abnormal states, we compared calculated and measured free thyroid hormone values in an additional population including pregnant women and hyperthyroid, hypothyroid, and "sick euthyroid" patients. Predictions based on the model were accurate in all these states except pregnancy, where there was some discrepancy between calculated and measured values for both hormones. In pregnant women with large abnormalities in thyroid-hormone-binding proteins, euthyroidism was accompanied by significantly lower free hormone concentrations, leading us to conclude that, in pregnancy, equilibrium may be reached at concentrations lower than those in other healthy subjects. Values for calculated and measured free thyroid hormones in "sick euthyroids" showed no discrepancy; however, we cannot exclude the possibility that non-dialyzable compounds are present that interfere with the hormone-protein binding.

scholarly journals Inverse Log-Linear Relationship between Thyroid-Stimulating Hormone and Free Thyroxine Measured by Direct Analog Immunoassay and Tandem Mass Spectrometry

2011 ◽  
Vol 57 (1) ◽  
pp. 122-127 ◽  
Author(s):  
Hendrick E van Deventer ◽  
Damodara R Mendu ◽  
Alan T Remaley ◽  
Steven J Soldin
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Linear Relationship ◽  
Correlation Coefficient ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Tandem Mass ◽  
Spearman Correlation ◽  
Log Linear ◽  
Stimulating Hormone

BACKGROUND Accurate measurement of free thyroxine (FT4) is important for diagnosing and managing thyroid disorders. Most laboratories measure FT4 by direct analogue immunoassay methods. The validity of these methods have recently been questioned. The inverse log-linear relationship between FT4 and thyroid-stimulating hormone (TSH) is well described and provides a physiological rationale on which to base an evaluation of FT4 assays. METHODS The study included 109 participants for whom FT4 measurement was requested by their clinician. Samples were selected for inclusion to reflect a wide spectrum of TSH and albumin results. FT4 and TSH were measured by use of the Siemens Immulite immunoassay (IA). FT4 was also measured by liquid chromatography–tandem mass spectrometry (LC-MS/MS) (MS-FT4). RESULTS The inverse log-linear correlation coefficient between TSH and FT4 was significantly better (P < 0.0001) for MS-FT4 (0.84, 95% CI, 0.77–0.88) than for IA-FT4 (0.45, 95% CI, 0.29–0.59). IA-FT4 showed a significant correlation with albumin (Spearman correlation coefficient 0.45, 95% CI, 0.29–0.5, P < 0.0001) and thyroxine-binding globulin (TBG) (Spearman correlation coefficient 0.23, 95% CI, 0.05–0.41, P = 0.02). In contrast, FT4 measurement by LC-MS/MS did not show a significant correlation with albumin or TBG. CONCLUSIONS The inverse log-linear relationship between FT4 and TSH was significantly better for FT4 measured by LC-MS/MS than by IA. The MS-FT4 method therefore provides FT4 results that agree clinically with those obtained for TSH. Additionally, the significant correlation between IA-FT4 with albumin and TBG suggests that this FT4 method depends on binding protein concentrations and consequently does not accurately reflect FT4.

scholarly journals Thyroid Hormone levels in Highlanders- A Comparison Between Residents of Two Altitudes in Nepal

2014 ◽  
Vol 11 (1) ◽  
pp. 18-21 ◽  
Author(s):  
O Nepal ◽  
BR Pokharel ◽  
K Khanal ◽  
P Gyawali ◽  
SL Malik ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
High Altitude ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
High Altitudes ◽  
Free Triiodothyronine ◽  
Sea Bed ◽  
High Altitude Natives ◽  
Stimulating Hormone

Background The endocrine changes related to altitude adaptation in human have attracted physiologists around the globe for long. A number of high altitude studies to detect the physiological changes have been performed now and then. But, the study to see the hormonal changes to compare populations residing at different high altitudes is a scarce. Hence, we have performed a study in native populations of different high altitude comparing changes in thyroid hormones in western Nepal. The Jharkot population included in this study is at altitude of 3760m and Jomsom population at 2800m height from sea bed. Objective The study is to compare changes in thyroid hormones at two different high altitude natives. Methods To compare thyroid status between high altitude natives at two different altitudes a cross sectional study is performed by random sampling method. The blood sample was collected in a vacutainer from fifty eight individuals after obtaining the informed consent of participants. The blood collected from antecubital vein was centrifuged in an hour and the serum obtained was used for biochemical analysis of free triiodothyronine, free thyroxine and thyroid stimulating hormone. Results Mean free thyroxine (fT4) of Jharkot population is significantly larger (p = 0.001) than Jomsom population. Mean thyroid stimulating hormone (TSH) with p = 0.597, does not indicate the difference between this two population. There is no significant difference between mean free triiodothyronine (fT3) of Jharkot and Jomsom population (p = 0.345). Conclusion The rise in free thyroid hormone at high altitude is not dependent on the thyroid stimulating hormone released from anterior pituitary. The rise in free thyroxine is found at higher altitude and no difference in fT3 level is detected in population studied at high altitudes. DOI: http://dx.doi.org/10.3126/kumj.v11i1.11017 Kathmandu University Medical Journal Vol.11(1) 2013: 18-21

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

2021 ◽  
Vol 53 (04) ◽  
pp. 272-279
Author(s):  
Chaochao Ma ◽  
Xiaoqi Li ◽  
Lixin Liu ◽  
Xinqi Cheng ◽  
Fang Xue ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pregnant Women ◽  
Early Pregnancy ◽  
Gestational Age ◽  
Dynamic Change ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Stimulating Hormone

AbstractThyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

scholarly journals Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor

1997 ◽  
Vol 43 (6) ◽  
pp. 957-962 ◽  
Author(s):  
Anthony G W Norden ◽  
Rodwin A Jackson ◽  
Lorraine E Norden ◽  
A Jane Griffin ◽  
Margaret A Barnes ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Rheumatoid Factor ◽  
Equilibrium Dialysis ◽  
Thyroid Stimulating Hormone ◽  
Normal Serum ◽  
Free Thyroxine ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Serum Free Thyroxine ◽  
Stimulating Hormone

Abstract A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM® or IMx® analyzers. “NETRIA” immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB® in 2 of 4 patients; AutoDELFIA®in 2 of the 5; and Corning ACS-180® and Bayer Diagnostics Immuno 1® in 1 of the 5. BM-ES700® system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient’s RhF concentration.

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