Agreement of Immunoassay and Tandem Mass Spectrometry in the Analysis of Cortisol and Free T4: Interpretation and Implications for Clinicians

Objective. To quantify differences in results obtained by immunoassays (IAs) and tandem mass spectrometry (MSMS) for cortisol and free thyroxine (FT4). Design & Patients. Cortisol was measured over 60 minutes following a standard ACTH stimulation test (n = 80); FT4 was measured over time in two cohorts of pregnant (n = 57), and nonpregnant (n = 28) women. Measurements. Samples were analyzed with both IA and MSMS. Results. Results for cortisol by the two methods tended to agree, but agreement weakened over the 60-minute test and was worse for higher (more extreme) concentrations. The results for FT4 depended on the method. IA measurements tended to agree with MSMS measurements when values fell within “normal levels”, but agreement was not constant across trimester in pregnant women and was poorest for the extreme (low/high) concentrations. Correlations between MSMS measurements and the difference between MSMS and IA results were strong and positive (0.411 < r < 0.823; all P < .05). Conclusions. IA and MSMS provide different measures of cortisol and FT4 at extreme levels, where clinical decision making requires the greatest precision. Agreement between the methods is inconsistent over time, is nonlinear, and varies with the analyte and concentrations. IA-based measurements may lead to erroneous clinical decisions

3,5-T2—A Janus-Faced Thyroid Hormone Metabolite Exerts Both Canonical T3-Mimetic Endocrine and Intracrine Hepatic Action

Over the last decades, thyroid hormone metabolites (THMs) received marked attention as it has been demonstrated that they are bioactive compounds. Their concentrations were determined by immunoassay or mass-spectrometry methods. Among those metabolites, 3,5-diiodothyronine (3,5-T2), occurs at low nanomolar concentrations in human serum, but might reach tissue concentrations similar to those of T4 and T3, at least based on data from rodent models. However, the immunoassay-based measurements in human sera revealed remarkable variations depending on antibodies used in the assays and thus need to be interpreted with caution. In clinical experimental approaches in euthyroid volunteers and hypothyroid patients using the immunoassay as the analytical tool no evidence of formation of 3,5-T2 from its putative precursors T4 or T3 was found, nor was any support found for the assumption that 3,5-T2 might represent a direct precursor for serum 3-T1-AM generated by combined deiodination and decarboxylation from 3,5-T2, as previously documented for mouse intestinal mucosa. We hypothesized that lowered endogenous production of 3,5-T2 in patients requiring T4 replacement therapy after thyroidectomy or for treatment of autoimmune thyroid disease, compared to production of 3,5-T2 in individuals with intact thyroid glands might contribute to the discontent seen in a subset of patients with this therapeutic regimen. So far, our observations do not support this assumption. However, the unexpected association between high serum 3,5-T2 and elevated urinary concentrations of metabolites related to coffee consumption requires further studies for an explanation. Elevated 3,5-T2 serum concentrations were found in several situations including impaired renal function, chronic dialysis, sepsis, non-survival in the ICU as well as post-operative atrial fibrillation (POAF) in studies using a monoclonal antibody-based chemoluminescence immunoassay. Pilot analysis of human sera using LC-linear-ion-trap-mass-spectrometry yielded 3,5-T2 concentrations below the limit of quantification in the majority of cases, thus the divergent results of both methods need to be reconciliated by further studies. Although positive anti-steatotic effects have been observed in rodent models, use of 3,5-T2 as a muscle anabolic, slimming or fitness drug, easily obtained without medical prescription, must be advised against, considering its potency in suppressing the HPT axis and causing adverse cardiac side effects. 3,5-T2 escapes regular detection by commercially available clinical routine assays used for thyroid function tests, which may be seriously disrupted in individuals self-administering 3,5-T2 obtained over-the counter or from other sources

3,5-T2-A Janus-Faced Thyroid Hormone Metabolite Exerts Both Canonical T3-Mimetic Endocrine and Intracrine Hepatic Action.

Over the last decades, thyroid hormone metabolites (THMs) received marked attention as it has been demonstrated that they are bioactive compounds. Their concentrations were determined by immunoassay or mass-spectrometry methods. Among those metabolites, 3,5-diiodothyronine (3,5-T2), occurs at low nanomolar concentrations in human serum, but might reach tissue concentrations similar to those of T4 and T3, at least based on data from rodent models. However, the immunoassay-based measurements in human sera revealed remarkable variations depending on antibodies used in the assays and thus need to be interpreted with caution. In clinical experimental approaches in euthyroid volunteers and hypothyroid patients using the immunoassay as the analytical tool no evidence of formation of 3,5-T2 from its putative precursors T4 or T3 was found, nor was any support found for the assumption that 3,5-T2 might represent a direct precursor for serum 3-T1-AM generated by combined deiodination and decarboxylation from 3,5-T2, as previously documented for mouse intestinal mucosa. We hypothesized that lowered endogenous production of 3,5-T2 in patients requiring T4 replacement therapy after thyroidectomy or for treatment of autoimmune thyroid disease, compared to production of 3,5-T2 in individuals with intact thyroid glands might contribute to the discontent seen in a subset of patients with this therapeutic regimen. So far, our observations do not support this assumption. However, the unexpected association between high serum 3,5-T2 and elevated urinary concentrations of metabolites related to coffee consumption requires further studies for an explanation. Elevated 3,5-T2 serum concentrations were found in several situations including impaired renal function, chronic dialysis, sepsis, non-survival in the ICU as well as post-operative atrial fibrillation (POAF) in studies using a monoclonal antibody-based chemoluminescence immunoassay. Pilot analysis of human sera using LC-linear-ion-trap-mass-spectrometry yielded 3,5-T2 concentrations below the limit of quantification in the majority of cases, thus the divergent results of both methods need to be reconciliated by further studies. Although positive anti-steatotic effects have been observed in rodent models, use of 3,5-T2 as a muscle anabolic, slimming or fitness drug, easily obtained without medical prescription, must be advised against, considering its potency in suppressing the HPT axis and causing adverse cardiac side effects. 3,5-T2 escapes regular detection by commercially available clinical routine assays used for thyroid function tests, which may be seriously disrupted in individuals self-administering 3,5-T2 obtained over-the counter or from other sources

3,5-T2-A Janus-Faced Thyroid Hormone Metabolite Exerts Both Canonical T3-Mimetic Endocrine and Intracrine Hepatic Action.

Over the last decades, thyroid hormone metabolites (THMs) received marked attention as it has been demonstrated that they are bioactive compounds. Their concentrations were determined by immunoassay or mass-spectrometry methods. Among those metabolites, 3,5-diiodothyronine (3,5-T2), occurs at low nanomolar concentrations in human serum, but might reach tissue concentrations similar to those of T4 and T3, at least based on data from rodent models. However, the immunoassay-based measurements in human sera revealed remarkable variations depending on antibodies used in the assays and thus need to be interpreted with caution. In clinical experimental approaches in euthyroid volunteers and hypothyroid patients using the immunoassay as the analytical tool no evidence of formation of 3,5-T2 from its putative precursors T4 or T3 was found, nor was any support found for the assumption that 3,5-T2 might represent a direct precursor for serum 3-T1-AM generated by combined deiodination and decarboxylation from 3,5-T2, as previously documented for mouse intestinal mucosa. We hypothesized that lowered endogenous production of 3,5-T2 in patients requiring T4 replacement therapy after thyroidectomy or for treatment of autoimmune thyroid disease, compared to production of 3,5-T2 in individuals with intact thyroid glands might contribute to the discontent seen in a subset of patients with this therapeutic regimen. So far, our observations do not support this assumption. However, the unexpected association between high serum 3,5-T2 and elevated urinary concentrations of metabolites related to coffee consumption requires further studies for an explanation. Elevated 3,5-T2 serum concentrations were found in several situations including impaired renal function, chronic dialysis, sepsis, non-survival in the ICU as well as post-operative atrial fibrillation (POAF) in studies using a monoclonal antibody-based chemoluminescence immunoassay. Pilot analysis of human sera using LC-linear-ion-trap-mass-spectrometry yielded 3,5-T2 concentrations below the limit of quantification in the majority of cases, thus the divergent results of both methods need to be reconciliated by further studies. Although positive anti-steatotic effects have been observed in rodent models, use of 3,5-T2 as a muscle anabolic, slimming or fitness drug, easily obtained without medical prescription, must be advised against, considering its potency in suppressing the HPT axis and causing adverse cardiac side effects. 3,5-T2 escapes regular detection by commercially available clinical routine assays used for thyroid function tests, which may be seriously disrupted in individuals self-administering 3,5-T2 obtained over-the counter or from other sources

Short-Term Time Trends in Prescribing Therapy for Hypothyroidism: Results of a Survey of American Thyroid Association Members

Objective: Hypothyroid patients frequently request specific therapies from their physicians. Combination therapy is vigorously discussed at professional meetings. We wished to determine if physician prescribing patterns for hypothyroidism changed during 2017 after specific educational events.Methods: A survey addressing treatment of hypothyroidism was emailed to American Thyroid Association (ATA) members on three occasions in 2017. The Spring emails were sent prior to a satellite symposium addressing hypothyroidism, and prior to the annual Endocrine Society and ATA meetings; the December emails were sent after these events. Physicians were presented with thirteen theoretical patients and chose from 6 therapeutic options, including levothyroxine, synthetic combination therapy, thyroid extract, and liothyronine monotherapy. The patient scenarios successively incorporated factors potentially providing reasons for considering combination therapy. Multivariate repeated measures logistic regression analyses first examined effects of physician characteristics on prescribing the various therapies. Then, analyses also incorporated timing, by comparing prescribing patterns in February, March, and December.Results: In analyses of prescribing levothyroxine monotherapy vs. any T3 therapy, there was a trend of borderline significance (p = 0.053) for T3 therapy to be prescribed more in December compared with February-March combined. When multivariate analyses were performed controlling for time and physician characteristics, choice of therapy was only significantly affected by country of practice (OR 1.7, CI 1.3–2.2). Physician choice of therapies was also examined for the options of continuing (1) levothyroxine, vs. (2) increasing levothyroxine, (3) adding liothyronine either with or without levothyroxine reduction, or (4) replacing levothyroxine with desiccated thyroid extract or liothyronine. When multivariate analyses incorporating time and physician characteristics were performed, respondents in December (OR 1.5, CI 1.0–2.3) and those practicing in North America (OR 1.8, CI 1.2–2.6) were more likely to prescribe liothyronine.Conclusions: This survey shows that although current North American guidelines do not recommend combination therapy, such therapy is being prescribed more over time and is also more commonly prescribed in North America. It is possible our guidelines are failing to incorporate evidence that physicians are considering when prescribing combination therapy. Such evidence could include data about patient preferences, and this needs to be a focus of future studies

Demonstration of reciprocal diurnal variation in human serum T3 and rT3 concentration demonstrated by mass spectrometric analysis and establishment of thyroid hormone reference intervals.

Background: There has been a wide range of reference intervals proposed in previous literature for thyroid hormones due to large between-assay variability of immunoassays, as well as lack of correction for collection time. We provided the diurnal reference intervals for five thyroid hormones, namely total thyroxine (TT4), total triiodothyronine (TT3), free thyroxine (FT4), free triiodothyronine (FT3), and reverse T3 (rT3), measured in serum samples of healthy participants using a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method. Methods: Couplet serum samples (a.m. and p.m.) were collected from 110 healthy females and 49 healthy males. Healthy volunteers were recruited from four participating centers between 2016 and 2018. Measurements of thyroid hormones were obtained by LC-MS/MS analysis. Results: Our study revealed significant uptrend in AM to PM FT4 ( Conclusion: When diagnosing thyroid disorders, it is important to have accurate measurement of thyroid hormones, and to acknowledge the diurnal fluctuation found, especially for FT3. Our study highlights the importance of standardization of collection times and implementation of LC-MS/MS in thyroid hormone measurement

Agreement of Immunoassay and Tandem Mass Spectrometry in the Analysis of Cortisol and Free T4: Interpretation and Implications for Clinicians

Objective. To quantify differences in results obtained by immunoassays (IAs) and tandem mass spectrometry (MSMS) for cortisol and free thyroxine (FT4). Design &amp; Patients. Cortisol was measured over 60 minutes following a standard ACTH stimulation test (n = 80); FT4 was measured over time in two cohorts of pregnant (n = 57), and nonpregnant (n = 28) women. Measurements. Samples were analyzed with both IA and MSMS. Results. Results for cortisol by the two methods tended to agree, but agreement weakened over the 60-minute test and was worse for higher (more extreme) concentrations. The results for FT4 depended on the method. IA measurements tended to agree with MSMS measurements when values fell within &quot;normal levels&quot;, but agreement was not constant across trimester in pregnant women and was poorest for the extreme (low/high) concentrations. Correlations between MSMS measurements and the difference between MSMS and IA results were strong and positive (0.411 &lt; r &lt; 0.823; all P &lt; .05). Conclusions. IA and MSMS provide different measures of cortisol and FT4 at extreme levels, where clinical decision making requires the greatest precision. Agreement between the methods is inconsistent over time, is nonlinear, and varies with the analyte and concentrations. IA-based measurements may lead to erroneous clinical decisions

Management of primary hypothyroidism: statement by the British Thyroid Association Executive Committee.

The management of primary hypothyroidism with levothyroxine (L-T4) is simple, effective and safe, and most patients report improved well-being on initiation of treatment. However, a proportion of individuals continue to suffer with symptoms despite achieving adequate biochemical correction. The management of such individuals has been the subject of controversy and of considerable public interest. The American Thyroid Association (ATA) and the European Thyroid Association (ETA) have recently published guidelines on the diagnosis and management of hypothyroidism. These guidelines have been based on extensive reviews of the medical literature and include sections on the role of combination therapy with L-T4 and liothyronine (L-T3) in individuals who are persistently dissatisfied with L-T4 therapy. This position statement by the British Thyroid Association (BTA) summarises the key points in these guidelines and makes recommendations on the management of primary hypothyroidism based on the current literature, review of the published positions of the ETA and ATA, and in line with best principles of good medical practice. The statement is endorsed by the Association of Clinical Biochemistry, (ACB), British Thyroid Foundation, (BTF), Royal College of Physicians (RCP) and Society for Endocrinology (SFE)

The role of clinicians in determining radioactive iodine use for low‐risk thyroid cancer

BACKGROUND: There is controversy regarding the optimal management of thyroid cancer. The proportion of patients with low‐risk thyroid cancer who received radioactive iodine (RAI) treatment increased over the last 20 years, and little is known about the role played by clinicians in hospital‐level RAI use for low‐risk disease. METHODS: Thyroid surgeons affiliated with 368 hospitals that had Commission on Cancer‐accredited cancer programs were surveyed. Survey data were linked to data reported to the National Cancer Database. A multivariable analysis was used to assess the relation between clinician decision makers and hospital‐level RAI use after total thyroidectomy in patients with stage I, well differentiated thyroid cancer. RESULTS: The survey response rate was 70% (560 of 804 surgeons). The surgeon was identified as the primary decision maker by 16% of the surgeons; the endocrinologist was identified as the primary decision maker by 69%, and a nuclear medicine, radiologist, or other physician was identified as the primary decision maker by 15%. In a multivariable analysis controlling for hospital case volume and hospital type, when the primary decision maker was in a specialty other than endocrinology or surgery, there was greater use of RAI at the hospital ( P < .001). A greater number of providers at the hospital where RAI was administered and having access to a tumor board also were associated with increased use of RAI ( P < .001 and P = .006, respectively). CONCLUSIONS: The specialty of the primary decision maker, the number of providers administering RAI, and having access to a tumor board were associated significantly with the use of RAI for stage I thyroid cancer. The findings have implications for addressing nonclinical variation between hospitals, with a marked heterogeneity in decision making suggesting that standardization of care will be challenging. Cancer 2013. © 2012 American Cancer Society. There is heterogeneity in clinician decision making for the management of patients with thyroid cancer. The specialty of the primary decision maker, the number of providers administering radioactive iodine, and access to a tumor board are associated significantly with the use of radioactive iodine for stage I thyroid cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96331/1/27721_ftp.pd

Prognosis of Differentiated Thyroid Cancer in Relation to Serum Thyrotropin and Thyroglobulin Antibody Status at Time of Diagnosis

BACKGROUND: Serum thyrotropin (TSH) concentration and thyroid autoimmunity may be of prognostic importance in differentiated thyroid cancer (DTC). Preoperative serum TSH level has been associated with higher DTC stage in cross-sectional studies; data are contradictory on the significance of thyroid autoimmunity at the time of diagnosis. OBJECTIVE: We sought to assess whether preoperative serum TSH and perioperative antithyroglobulin antibodies (TgAb) were associated with thyroid cancer stage and outcome in DTC patients followed by the National Thyroid Cancer Treatment Cooperative Study, a large multicenter thyroid cancer registry. METHODS: Patients registered after 1996 with available preoperative serum TSH (n=617; the TSH cohort) or perioperative TgAb status (n=1770; the TgAb cohort) were analyzed for tumor stage, persistent disease, recurrence, and overall survival (OS; median follow-up, 5.5 years). Parametric tests assessed log-transformed TSH, and categorical variables were tested with chi square. Disease-free survival (DFS) and OS was assessed with Cox models. RESULTS: Geometric mean serum TSH levels were higher in patients with higher-stage disease (Stage III/IV=1.48 vs. 1.02 mU/L for Stages I/II; p=0.006). The relationship persisted in those aged ≥45 years after adjusting for sex (p=0.01). Gross extrathyroidal extension (p=0.03) and presence of cervical lymph node metastases (p=0.003) were also significantly associated with higher serum TSH. Disease recurrence and all-cause mortality occurred in 37 and 38 TSH cohort patients respectively, which limited the power for survival analysis. Positive TgAb was associated with lower stage on univariate analysis (positive TgAb in 23.4% vs. 17.8% of Stage I/II vs. III/IV patients, respectively; p=0.01), although the relationship lost significance when adjusting for age and sex (p=0.34). Perioperative TgAb was not an independent predictor of DFS (hazard ratio=1.12 [95% confidence interval=0.74-1.69]) or OS (hazard ratio=0.98 [95% confidence interval=0.56-1.72]). CONCLUSIONS: Preoperative serum TSH level is associated with higher DTC stage, gross extrathyroidal extension, and neck node metastases. Perioperative TgAb is not an independent predictor of DTC prognosis. A larger cohort is required to assess whether preoperative serum TSH level predicts recurrence or mortality