Thyroglobulin Cutoff Values for Detecting Excellent Response to Therapy in Patients With Differentiated Thyroid Cancer.

Context: Serum thyroglobulin (Tg) is a biochemical marker for detecting persistent or recurrent differentiated thyroid carcinoma (DTC) post-thyroidectomy. Tg can indicate DTC before structural disease (SD) is visible with imaging procedures. Objective: This work aimed to evaluate the clinical performance of the Elecsys® Tg II assay at a Tg cutoff of 0.2 ng/mL for ruling out SD in adults with DTC after total/near-total thyroidectomy, with or without radioiodine ablation (RAI). Methods: Patients were enrolled into 2 cohorts: longitudinal (Tg assessed every 6 months over 2 years under thyroid-stimulating hormone [TSH] suppression therapy following thyroidectomy with or without RAI) and cross-sectional with confirmed SD (Tg assessed once >12 weeks after thyroidectomy). Analyses were performed for both cohorts combined and in the longitudinal cohort. Results: The study included 530 clinically evaluable samples, the majority (n = 424 samples) from patients who had not received RAI treatment. Following correction for SD prevalence (4.97% in the longitudinal cohort), an Elecsys Tg II cutoff of 0.2 ng/mL ruled out SD with a negative predictive value of 99.9% (95% CI, 99.5%-100%). The assay had excellent sensitivity (98.5%-100%) and acceptable specificity (53.4%-53.5%) for detecting SD (Tg ≥ 0.2 ng/mL) for both cohorts combined and in the longitudinal cohort, with similar findings in RAI-treated and non-RAI-treated subgroups. Conclusion: In this cohort of DTC patients post-thyroidectomy, a Tg cutoff of 0.2 ng/mL was highly effective for ruling out the presence of SD under TSH-suppressed conditions, including in patients who had not received RAI treatment.

A Retrospective Evaluation of the Diagnostic Performance of an Interdependent Pairwise MicroRNA Expression Analysis with a Mutation Panel in Indeterminate Thyroid Nodules.

Background: The addition of genetic analysis to the evaluation of thyroid nodule fine-needle aspiration biopsy samples improves diagnostic accuracy of cytologically indeterminate thyroid nodules (ITNs) with Bethesda III or IV cytopathology. We previously reported the performance of a multiplatform molecular test, referred to in this study as MPTXv1, that includes a mutation panel (ThyGeNEXT®) plus an algorithmic microRNA (miRNA) risk classifier (ThyraMIR®). Complex interactions of growth-promoting and -suppressing miRNAs affect the phenotype. We previously demonstrated that accounting for these interactions with pairwise miRNA expression analysis improves the diagnosis of medullary thyroid carcinoma. In this study, we assess the impact of pairwise miRNA expression analysis on risk stratification of ITNs. Methods: Pairwise expression analysis of 11 miRNAs was performed on a training cohort of histopathology-proven benign nodules (n = 50) to define the mean and standard deviation of each pairwise analysis and create a Benign/Malignant Profiler (MPTXv2), deviations from which predicted the malignancy risk. Clinical validation of MPTXv2 was assessed using a cohort of 178 ITN (Bethesda III and IV) samples from a multicentered, blinded retrospective study, previously evaluated by MPTXv1. Results: Compared with MPTXv1, MPTXv2 significantly improved the test performance. The receiver operating characteristic (ROC) areas under the curve (AUC) increased from 0.85 to 0.97 (p < 0.001), and the diagnostic accuracy at the positive threshold increased significantly (p < 0.05) from 83% [95% confidence interval (CI) = 76-88] to 93% [CI = 89-96]. The significant improvement in the ROC AUC and the diagnostic accuracy was due to a strong statistical trend for improvement in specificity at the positive threshold. At the positive threshold, the specificity for MPTXv1 was 90% [CI = 84-95] and improved to 98% [CI = 94-99] for MPTXv2. Using the MPTXv2, the Moderate-Risk cohort decreased from 50 samples (28% of the cohort) to 24 samples (13% of the cohort). This 52% decrease is statistically significant (p < 0.001) and clinically meaningful. Conclusion: As compared with MPTXv1, pairwise miRNA expression analysis used in MPTXv2 significantly improved the diagnostic accuracy of ITN risk stratification and reduced the size of the Moderate-Risk group. Prospective trials are indicated to confirm these findings in a clinical practice setting.

American Association of Clinical Endocrinology And Associazione Medici Endocrinologi Thyroid Nodule Algorithmic Tool.

OBJECTIVE: The first edition of the American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi Guidelines for the Diagnosis and Management of Thyroid Nodules was published in 2006 and updated in 2010 and 2016. The American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi multidisciplinary thyroid nodules task force was charged with developing a novel interactive electronic algorithmic tool to evaluate thyroid nodules. METHODS: The Thyroid Nodule App (termed TNAPP) was based on the updated 2016 clinical practice guideline recommendations while incorporating recent scientific evidence and avoiding unnecessary diagnostic procedures and surgical overtreatment. This manuscript describes the algorithmic tool development, its data requirements, and its basis for decision making. It provides links to the web-based algorithmic tool and a tutorial. RESULTS: TNAPP and TI-RADS were cross-checked on 95 thyroid nodules with histology-proven diagnoses. CONCLUSION: TNAPP is a novel interactive web-based tool that uses clinical, imaging, cytologic, and molecular marker data to guide clinical decision making to evaluate and manage thyroid nodules. It may be used as a heuristic tool for evaluating and managing patients with thyroid nodules. It can be adapted to create registries for solo practices, large multispecialty delivery systems, regional and national databases, and research consortiums. Prospective studies are underway to validate TNAPP to determine how it compares with other ultrasound-based classification systems and whether it can improve the care of patients with clinically significant thyroid nodules while reducing the substantial burden incurred by those who do not benefit from further evaluation and treatment.

American Association of Clinical Endocrinology And Associazione Medici Endocrinologi Thyroid Nodule Algorithmic Tool.

OBJECTIVE: The first edition of the American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi Guidelines for the Diagnosis and Management of Thyroid Nodules was published in 2006 and updated in 2010 and 2016. The American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi multidisciplinary thyroid nodules task force was charged with developing a novel interactive electronic algorithmic tool to evaluate thyroid nodules. METHODS: The Thyroid Nodule App (termed TNAPP) was based on the updated 2016 clinical practice guideline recommendations while incorporating recent scientific evidence and avoiding unnecessary diagnostic procedures and surgical overtreatment. This manuscript describes the algorithmic tool development, its data requirements, and its basis for decision making. It provides links to the web-based algorithmic tool and a tutorial. RESULTS: TNAPP and TI-RADS were cross-checked on 95 thyroid nodules with histology-proven diagnoses. CONCLUSION: TNAPP is a novel interactive web-based tool that uses clinical, imaging, cytologic, and molecular marker data to guide clinical decision making to evaluate and manage thyroid nodules. It may be used as a heuristic tool for evaluating and managing patients with thyroid nodules. It can be adapted to create registries for solo practices, large multispecialty delivery systems, regional and national databases, and research consortiums. Prospective studies are underway to validate TNAPP to determine how it compares with other ultrasound-based classification systems and whether it can improve the care of patients with clinically significant thyroid nodules while reducing the substantial burden incurred by those who do not benefit from further evaluation and treatment.

Multiplatform molecular test performance in indeterminate thyroid nodules.

BACKGROUND: Approximately 25% of thyroid nodule fine-needle aspirates (FNAs) have cytology that is indeterminate for malignant disease. Accurate risk stratification of these FNAs with ancillary testing would reduce unnecessary thyroid surgery. METHODS: We evaluated the performance of an ancillary multiplatform test (MPTX) that has three diagnostic categories (negative, moderate, and positive). MPTX includes the combination of a mutation panel (ThyGeNEXT®) and a microRNA risk classifier (ThyraMIR®). A blinded, multicenter study was performed using consensus histopathology diagnosis among three pathologists to validate test performance. RESULTS: Unanimous consensus diagnosis was reached in 197 subjects with indeterminate thyroid nodules; 36% had disease. MPTX had 95% sensitivity (95% CI,86%-99%) and 90% specificity (95% CI,84%-95%) for disease in prevalence adjusted nodules with Bethesda III and IV cytology. Negative MPTX results ruledout disease with 97% negative predictive value (NPV; 95% CI,91%-99%) at a 30% disease prevalence, while positive MPTX results ruledin high risk disease with 75% positive predictive value (PPV; 95% CI,60%-86%). Such results are expected in four out of five Bethesda III and IV nodules tested, including RAS positive nodules in which the microRNA classifier was useful in rulingin disease. 90% of mutation panel false positives were due to analytically verified RAS mutations detected in benign adenomas. Moderate MPTX results had a moderate rate of disease (39%, 95% CI,23%-54%), primarily due to RAS mutations, wherein the possibility of disease could not be excluded. CONCLUSIONS: Our results emphasize that decisions for surgery should not solely be based on RAS or RAS-like mutations. MPTX informs management decisions while accounting for these challenges.

Implementing Key Changes in the American Thyroid Association 2015 Thyroid Nodules/Differentiated Thyroid Cancer Guidelines Across Practice Types.

OBJECTIVE: This article provides suggestions to help clinicians implement important changes in the 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma ("ATA 2015") across diverse settings. METHODS: Key ATA 2015 changes are summarized regarding: ( 1) thyroid nodule management; ( 2) lobectomy versus thyroidectomy for differentiated thyroid carcinoma (DTC); and ( 3) surveillance following primary treatment of DTC. Advice to facilitate implementation is based on clinical experience and selected literature. RESULTS: Strategies are described to enhance acquisition of high-quality information that helps identify patients who may possibly avoid fine-needle aspiration (FNA) of thyroid nodules or total thyroidectomy for DTC, or undergo less intense postoperative surveillance. Sonographic imaging of nodules may improve if sonograms are obtained by clinicians ordering or performing FNA or trusted high-volume sonographers. Cytopathologic assessment and reporting can be improved by working with regional or national experts. Pre-operative evaluation by endocrinologists is important so that patients are referred to experienced, proficient surgeons and assisted with well-informed decision-making regarding surgical radicality. Endocrinologists and surgeons should ensure performance of pre-operative neck ultrasonography, voice/laryngeal evaluation, and contrast-enhanced cross-sectional imaging when appropriate. Findings should be disseminated to all healthcare team members, ideally through a comprehensive medical record accessible to the entire team. CONCLUSION: Optimization of the sequence of specialist visits and assembly of interactive multidisciplinary teams coupled with intensified interdisciplinary and patient communication may enable clinicians to more effectively implement ATA 2015, which calls for more individualized, and often, less "invasive" management of thyroid nodules and DTC. ABBREVIATIONS: ATA 2009 = 2009 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma; ATA 2015 = 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma; DTC = differentiated thyroid carcinoma; FNA = fine-needle aspiration; PET/CT = positron emission tomography/computed tomography.

Heterogeneity in Positive Predictive Value of RAS Mutations in Cytologically Indeterminate Thyroid Nodules.

BACKGROUND: RAS mutations are common in the available mutational analysis of cytologically indeterminate (Cyto-I) thyroid nodules. However, their reported positive predictive value (PPV) for cancer is widely variable. The reason for this variability is unknown, and it causes clinical management uncertainty. A systematic review was performed, evaluating the PPV for cancer in RAS mutation positive Cyto-I nodules, and variables that might affect residual heterogeneity across the different studies were considered. METHODS: PubMed was searched through February 22, 2017, including studies that evaluated at least one type of RAS mutation in Cyto-I nodules, including any (or all) of the Bethesda III/IV/V categories or their equivalents and where the histological diagnosis was available. The PPV residual heterogeneity was investigated after accounting for Bethesda classification, blindedness of the histopathologist to the RAS mutational status, Bethesda category-specific cancer prevalence for each study, and which RAS genes and codons were tested. This was studied using five meta-regression models fit to different sets of Bethesda classification categories: Bethesda III, IV, or V (III/IV/V); Bethesda III or IV (III/IV); Bethesda III only; Bethesda IV only; and Bethesda V only. RESULTS: Of 1831 studies, 23 were eligible for data inclusion. Wide ranges of PPV were found at 0-100%, 28-100%, and 0-100% in Bethesda III, IV, and V, respectively. Residual heterogeneity remained moderately high for PPV after accounting for the above moderators for Bethesda III/IV/V (21 studies; I2 = 59.5%) and Bethesda III/IV (19 studies; I2 = 66.0%), with significant Cochran's Q-test for residual heterogeneity (p < 0.001). Among individual Bethesda categories, residual heterogeneity was: Bethesda III (eight studies; I2 = 89.0%), IV (12 studies; I2 = 53.5%), and V (10 studies; I2 = 34.4%), with significant Cochran's Q-test for Bethesda III (p < 0.001) and IV (p = 0.04). CONCLUSION: The PPV of RAS mutations in Bethesda III and IV categories is quite heterogeneous across different studies, creating low confidence in the accuracy of a single estimate of PPV. Clinicians must appreciate this wide variability when managing a RAS-mutated Cyto-I nodule. Future studies should seek to resolve this unexplained variability.

United States and European Multicenter Prospective Study for the Analytical Performance and Clinical Validation of a Novel Sensitive Fully Automated Immunoassay for Calcitonin.

BACKGROUND: The objective of this study is the validation and proof of clinical relevance of a novel electrochemiluminescence immunoassay (ECLIA) for the determination of serum calcitonin (CT) in patients with medullary thyroid carcinoma (MTC) and in different diseases of the thyroid and of calcium homeostasis. METHODS: This was a multicenter prospective study on basal serum CT concentrations performed in 9 US and European referral institutions. In addition, stimulated CT concentrations were measured in 50 healthy volunteers after intravenous calcium administration (2.5 mg/kg bodyweight). RESULTS: In total, 1929 patients and healthy controls were included. Limits of blank, detection, and quantification for the ECLIA were 0.3, 0.5, and 1 ng/L, respectively. Highest intra- and interassay coefficients of variation were 7.4% (CT concentration, 0.8 ng/L) and 7.0% (1.1 ng/L), respectively. Medians (interval) of serum CT concentrations in 783 healthy controls were 0.8 ng/L (<0.5-12.7) and 3 ng/L (<0.5-18) for females and males, respectively (97.5th percentile, 6.8 and 11.6 ng/L, respectively). Diagnostic sensitivity and specificity were 100%/97.1% and 96.2%/96.4%, for female/males, respectively. Patients (male/female) with primary hyperparathyroidism, renal failure, and neuroendocrine tumors showed CT concentrations >97.5th percentile in 33%/4.7%, 18.5%/10%, and 8.3%/12%, females/males, respectively. Peak serum CT concentrations were reached 2 min after calcium administration (161.7 and 111.8 ng/L in males and females, respectively; P < 0.001). CONCLUSIONS: Excellent analytical performance, low interindividual variability, and low impact of confounders for increased CT concentrations in non-MTC patients indicate that the investigated assay has appropriate clinical utility. Calcium-stimulated CT results suggest good test applicability owing to low interindividual variability.

Improving the adoption of thyroid cancer clinical practice guidelines.

OBJECTIVES/HYPOTHESIS: To present an overview of the barriers to the implementation of clinical practice guidelines (CPGs) in thyroid cancer management and to introduce a computer-based clinical support system. DATA SOURCES: PubMed. REVIEW METHODS: A review of studies on adherence to CPGs was conducted. RESULTS: Awareness and adoption of CPGs is low in thyroid cancer management. Barriers to implementation include unfamiliarity with the CPGs and financial concerns. Effective interventions to improve adherence are possible, especially when they are readily accessible at the point of care delivery. Computerized clinical support systems show particular promise. The authors introduce the clinical decision making modules (CDMMs) of the Thyroid Cancer Care Collaborative, a thyroid cancer-specific electronic health record. These computer-based modules can assist clinicians with implementation of these recommendations in clinical practice. CONCLUSION: Computer-based support systems can help clinicians understand and adopt the thyroid cancer CPGs. By integrating patient characteristics and guidelines at the point of care delivery, the CDMMs can improve adherence to the guidelines and help clinicians provide high-quality, evidence-based, and individualized patient care in the management of differentiated thyroid cancer. Laryngoscope, 126:2640-2645, 2016.

TRANSCULTURALIZATION RECOMMENDATIONS FOR DEVELOPING LATIN AMERICAN CLINICAL PRACTICE ALGORITHMS IN ENDOCRINOLOGY--PROCEEDINGS OF THE 2015 PAN-AMERICAN WORKSHOP BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY.

The American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE) convened their first Workshop for recommendations to optimize Clinical Practice Algorithm (CPA) development for Latin America (LA) in diabetes (focusing on glycemic control), obesity (focusing on weight loss), thyroid (focusing on thyroid nodule diagnostics), and bone (focusing on postmenopausal osteoporosis) on February 28, 2015, in San Jose, Costa Rica. A standardized methodology is presented incorporating various transculturalization factors: resource availability (including imaging equipment and approved pharmaceuticals), health care professional and patient preferences, lifestyle variables, socio-economic parameters, web-based global accessibility, electronic implementation, and need for validation protocols. A standardized CPA template with node-specific recommendations to assist the local transculturalization process is provided. Participants unanimously agreed on the following five overarching principles for LA: (1) there is only one level of optimal endocrine care, (2) hemoglobin A1C should be utilized at every level of diabetes care, (3) nutrition education and increased pharmaceutical options are necessary to optimize the obesity care model, (4) quality neck ultrasound must be part of an optimal thyroid nodule care model, and (5) more scientific evidence is needed on osteoporosis prevalence and cost to justify intervention by governmental health care authorities. This 2015 AACE/ACE Workshop marks the beginning of a structured activity that assists local experts in creating culturally sensitive, evidence-based, and easy-to-implement tools for optimizing endocrine care on a global scale.

ACTIVE SURVEILLANCE FOR PAPILLARY THYROID MICROCARCINOMA: NEW CHALLENGES AND OPPORTUNITIES FOR THE HEALTH CARE SYSTEM.

OBJECTIVE: The dramatic increase in papillary thyroid carcinoma (PTC) is primarily a result of early diagnosis of small cancers. Active surveillance is a promising management strategy for papillary thyroid microcarcinomas (PTMCs). However, as this management strategy gains traction in the U.S., it is imperative that patients and clinicians be properly educated, patients be followed for life, and appropriate tools be identified to implement the strategy. METHODS: We review previous active surveillance studies and the parameters used to identify patients who are good candidates for active surveillance. We also review some of the challenges to implementing active surveillance protocols in the U.S. and discuss how these might be addressed. RESULTS: Trials of active surveillance support nonsurgical management as a viable and safe management strategy. However, numerous challenges exist, including the need for adherence to protocols, education of patients and physicians, and awareness of the impact of this strategy on patient psychology and quality of life. The Thyroid Cancer Care Collaborative (TCCC) is a portable record keeping system that can manage a mobile patient population undergoing active surveillance. CONCLUSION: With proper patient selection, organization, and patient support, active surveillance has the potential to be a long-term management strategy for select patients with PTMC. In order to address the challenges and opportunities for this approach to be successfully implemented in the U.S., it will be necessary to consider psychological and quality of life, cultural differences, and the patient's clinical status.

Molecular Testing for miRNA, mRNA, and DNA on Fine-Needle Aspiration Improves the Preoperative Diagnosis of Thyroid Nodules With Indeterminate Cytology.

CONTEXT: Molecular testing for oncogenic mutations or gene expression in fine-needle aspirations (FNAs) from thyroid nodules with indeterminate cytology identifies a subset of benign or malignant lesions with high predictive value. OBJECTIVE: This study aimed to evaluate a novel diagnostic algorithm combining mutation detection and miRNA expression to improve the diagnostic yield of molecular cytology. SETTING: Surgical specimens and preoperative FNAs (n = 638) were tested for 17 validated gene alterations using the miRInform Thyroid test and with a 10-miRNA gene expression classifier generating positive (malignant) or negative (benign) results. DESIGN: Cross-sectional sampling of thyroid nodules with atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) or follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) cytology (n = 109) was conducted at 12 endocrinology centers across the United States. Qualitative molecular results were compared with surgical histopathology to determine diagnostic performance and model clinical effect. RESULTS: Mutations were detected in 69% of nodules with malignant outcome. Among mutation-negative specimens, miRNA testing correctly identified 64% of malignant cases and 98% of benign cases. The diagnostic sensitivity and specificity of the combined algorithm was 89% (95% confidence interval [CI], 73-97%) and 85% (95% CI, 75-92%), respectively. At 32% cancer prevalence, 61% of the molecular results were benign with a negative predictive value of 94% (95% CI, 85-98%). Independently of variations in cancer prevalence, the test increased the yield of true benign results by 65% relative to mRNA-based gene expression classification and decreased the rate of avoidable diagnostic surgeries by 69%. CONCLUSIONS: Multiplatform testing for DNA, mRNA, and miRNA can accurately classify benign and malignant thyroid nodules, increase the diagnostic yield of molecular cytology, and further improve the preoperative risk-based management of benign nodules with AUS/FLUS or FN/SFN cytology.

Striving toward standardization of reporting of ultrasound features of thyroid nodules and lymph nodes: a multidisciplinary consensus statement.

BACKGROUND: The use of high-resolution ultrasound (US) imaging is a mainstay of the initial evaluation and long-term management of thyroid nodules and thyroid cancer. To fully capitalize on the diagnostic capabilities of a US examination in the context of thyroid disease, many clinicians consider it desirable to establish a universal format and standard of US reporting. The goals of this interdisciplinary consensus statement are twofold. First, to create a standardized set of US features to characterize thyroid nodules and cervical lymph nodes accurately, and second, to create a standardized system for tracking sequential changes in the US examination of thyroid nodules and cervical lymph nodes for the purpose of determining risk of malignancy. SUMMARY: The Thyroid, Head and Neck Cancer (THANC) Foundation convened a panel of nine specialists from a variety of medical disciplines that are actively involved in the diagnosis and treatment of thyroid nodules and thyroid cancer. Consensus was achieved on the following topics: US evaluation of the thyroid gland, US evaluation of thyroid nodules, US evaluation of cervical lymph nodes, US-guided fine needle aspiration (FNA) of thyroid nodules, and US-guided FNA of cervical lymph nodes. CONCLUSION: We propose that this statement represents a consensus within a multidisciplinary team on the salient and essential elements of a comprehensive and clinically significant thyroid and neck US report with regards to content, terminology, and organization. This reporting protocol supplements previous US performance guidelines by not only capturing categories of findings that may have important clinical implications, but also delineating findings that are clinically relevant within those categories as specifically as possible. Additionally, we have included the specific features of diagnostic and therapeutic interventions that have not been previously addressed.

Analytical performance verification of a molecular diagnostic for cytology-indeterminate thyroid nodules.

OBJECTIVE: Our objective was to verify the analytical performance of the Afirma gene expression classifier (GEC) in the classification of cytologically indeterminate thyroid nodule fine-needle aspirates (FNAs). DESIGN: Analytical performance studies were designed to characterize the stability of RNA in FNAs during collection and shipment, analytical sensitivity as applied to input RNA concentration and malignant/benign FNA mixtures, analytical specificity (i.e. potentially interfering substances) as tested on blood and genomic DNA, and assay performance studies including intra-nodule, intraassay, inter-assay, and inter-laboratory reproducibility. RESULTS: RNA content within FNAs preserved in FNAProtect is stable for up to 6 d at room temperature with no changes in RNA yield (P = 0.58) or quality (P = 0.56). FNA storage and shipping temperatures were found to have no significant effect on GEC scores (P = 0.55) or calls (100% concordance). Analytical sensitivity studies demonstrated tolerance to variation in RNA input (5-25 ng) and to the dilution of malignant FNA material down to 20%. Analytical specificity studies using malignant samples mixed with blood (up to 83%) and genomic DNA (up to 30%) demonstrated negligible assay interference with respect to false-negative calls, although benign FNA samples mixed with relatively high proportions of blood demonstrated a potential for false-positive calls. The test is reproducible from extraction through GEC result, including variation across operators, runs, reagent lots, and laboratories (sd of 0.158 for scores on a >6 unit scale). CONCLUSIONS: Analytical sensitivity, analytical specificity, robustness, and quality control of the GEC were successfully verified, indicating its suitability for clinical use.

Graves' disease: diagnostic and therapeutic challenges (multimedia activity).

Graves' disease is the most common cause of hyperthyroidism in the United States. Graves' disease occurs more often in women with a female:male ratio of 5:1 and a population prevalence of 1% to 2%. A genetic determinant to the susceptibility to Graves' disease is suspected because of familial clustering of the disease, a high sibling recurrence risk, the familial occurrence of thyroid autoantibodies, and the 30% concordance in disease status between identical twins. Graves' disease is an autoimmune thyroid disorder characterized by the infiltration of immune effector cells and thyroid antigen-specific T cells into the thyroid and thyroid-stimulating hormone receptor expressing tissues, with the production of autoantibodies to well-defined thyroidal antigens, such as thyroid peroxidase, thyroglobulin, and the thyroid-stimulating hormone receptor. The thyroid-stimulating hormone receptor is central to the regulation of thyroid growth and function. Stimulatory autoantibodies in Graves' disease activate the thyroid-stimulating hormone receptor leading to thyroid hyperplasia and unregulated thyroid hormone production and secretion. Below-normal levels of baseline serum thyroid-stimulating hormone receptor, normal to elevated serum levels of T4, elevated serum levels of T3 and thyroid-stimulating hormone receptor autoantibodies, and a diffusely enlarged, heterogeneous, hypervascular (increased Doppler flow) thyroid gland confirm diagnosis of Graves' disease (available at: http://supplements.amjmed.com/2010/hyperthyroid/faculty.php). This Resource Center is also available through the website of The American Journal of Medicine (www.amjmed.com). Click on the "Thyroid/Graves' Disease" link in the "Resource Centers" section, found on the right side of the Journal homepage.