IGF-1 as screening tool for acromegaly and adult-onset growth hormone deficiency in the Netherlands.

OBJECTIVE: Insulin-like growth factor 1 (IGF-1) measurements play a central role in the diagnosis and follow-up of acromegaly and growth hormone deficiency. However, improving health care outcomes for these patients involves an intricate process of laboratory diagnostics and skilled health care professionals. The integrated effects of IGF-1 reports on diagnosis and treatment decisions are yet unknown. DESIGN, PATIENTS AND MEASUREMENTS: Extended quality assessment, distributing the description of five (real) patient cases with accompanying blood samples. Patients suspected or during follow up for acromegaly or adult onset of growth hormone deficiency were included. Laboratory specialists and endocrinologists in the same centre were asked to interpret their centre-specific IGF-1 results by using a laboratory and medical questionnaire. This way, insight could be obtained into the combined effects of different assays, assay harmonisation, reference value sets, and individual physician interpretation in relation to guidelines, thus reviewing the entire diagnostic and management process. RESULTS: Limited variation (CV 13.8 ± 2.8) was found in IGF-1 concentrations despite different use of the harmonization sample and factor among laboratories. This interlaboratory variation increased upon conversion to SD scores (CV 15.7 ± 40.7) as a consequence of the use of different reference value sets. Furthermore, there was a lack of adherence to international guidelines among endocrinologists. CONCLUSIONS: Highly variable diagnostic and treatment outcomes in acromegaly and AGHD in the Netherlands can be attributed to increased variability of IGF-1 upon conversion to SD scores and low adherence to clinical guidelines.

Adult mouse and human organoids derived from thyroid follicular cells and modeling of Graves' hyperthyroidism.

The thyroid maintains systemic homeostasis by regulating serum thyroid hormone concentrations. Here we report the establishment of three-dimensional (3D) organoids from adult thyroid tissue representing murine and human thyroid follicular cells (TFCs). The TFC organoids (TFCOs) harbor the complete machinery of hormone production as visualized by the presence of colloid in the lumen and by the presence of essential transporters and enzymes in the polarized epithelial cells that surround a central lumen. Both the established murine as human thyroid organoids express canonical thyroid markers PAX8 and NKX2.1, while the thyroid hormone precursor thyroglobulin is expressed at comparable levels to tissue. Single-cell RNA sequencing and transmission electron microscopy confirm that TFCOs phenocopy primary thyroid tissue. Thyroid hormones are readily detectable in conditioned medium of human TFCOs. We show clinically relevant responses (increased proliferation and hormone secretion) of human TFCOs toward a panel of Graves' disease patient sera, demonstrating that organoids can model human autoimmune disease.

Diurnal salivary androstenedione and 17-hydroxyprogesterone levels in healthy volunteers for monitoring treatment efficacy of patients with congenital adrenal hyperplasia.

OBJECTIVE: Treatment of congenital adrenal hyperplasia (CAH) patients with glucocorticoids is often challenging since there is a delicate balance between over- and undertreatment. Treatment can be monitored noninvasively by measuring salivary androstenedione (A4) and 17-hydroxyprogesterone (17-OHP). Optimal treatment monitoring requires the establishment of reference values in saliva. DESIGN: A descriptive study. PATIENTS: For this study saliva of 255 healthy paediatric and adult volunteers with an age range of 4-75 years old was used. MEASUREMENTS: We developed a sensitive liquid chromatography-tandem mass spectrometry method, assessed salivary A4 and 17-OHP stability, and measured A4 and 17-OHP concentrations in saliva collected in the morning, afternoon, and evening. RESULTS: We quantified A4 and 17-OHP concentrations in the morning, afternoon, and evening and demonstrated that there is a significant rhythm with the highest levels in the morning and decreasing levels over the day. A4 and 17-OHP concentrations display an age-dependent pattern. These steroids remain stable in saliva at ambient temperature for up to 5 days. CONCLUSIONS: Good stability of the steroids in saliva enables saliva collection by the patient at home. Since salivary A4 and 17-OHP display a diurnal rhythm and age-dependent pattern, we established reference values for both children and adults at three time points during the day. These reference values support treatment monitoring of children and adults with CAH.

Testosterone analysis in castrated prostate cancer patients: suitability of the castration cut-off and analytical accuracy of the present-day clinical immunoassays.

OBJECTIVES: Testosterone testing is relevant for evaluating castration adequacy and diagnosis of castration-resistant prostate cancer (PCa). However, the recommended testosterone cut-off of 1.7 nmol/L (50 ng/dL) to define adequate castration is based on consensus and not validated for the automated immunoassays (AIA) used in today's medical laboratories. Furthermore, appropriate population intervals have not been determined by a state-of-the-art assay. We investigated the analytical suitability of this cut-off and the accuracy of the present-day AIAs for testosterone analysis in castrated PCa patients. METHODS: Leftover serum from 120 PCa patients castrated with luteinizing hormone-releasing hormone agonists was analysed for testosterone by five methods: Architect i2000 (Abbott), Access (Beckman), Cobas 6000 (Roche), Atellica (Siemens), LC-MS/MS. For all assays, the castration 95th, 97.5th and 99th percentile upper limits were determined. Furthermore, Passing-Bablok regression, mean bias and Spearman's correlation coefficients were compared to the LC-MS/MS method and total error based on biological variation. RESULTS: All castration upper limits, ranging from 0.472 nmol/L (LC-MS/MS) to 1.25 nmol/L (Access) (95% percentile), were significantly lower than the current castration cut-off (1.7 nmol/L). Slopes of Passing-Bablok regressions comparing the AIA with the LC-MS/MS method ranged from 1.4 (Cobas and Atellica) to 3.8 (Access). The Architect showed the highest correlation with LC-MS/MS (ρ=0.58). All AIA failed to meet the desirable total error criterion. CONCLUSIONS: These results suggest that a lower general testosterone castration cut-off may be more appropriate in evaluating the adequacy of castration in PCa and that present-day AIA lack analytical accuracy to quantify testosterone levels in castrated PCa.

Evaluation of the Atellica® UAS 800: a new member of the automated urine sediment analyzer family.

BACKGROUND: In 2017 the Atellica® UAS 800 urine sediment analyzer was introduced by Siemens Healthineers. We investigated its applicability in the standardization and automation of the laboratory urinalysis workflow, including the prediction of urine culture outcome and glomerular pathology. METHODS: We evaluated the performance characteristics of the Atellica® UAS 800 and its correlation with the iQ200 (Beckman Coulter). In addition, we studied the agreement between Atellica® UAS 800 and CLINITEK Novus® and determined the predictive value of bacteria and leukocyte counts for urine culture outcome. Furthermore, we investigated the ability of Atellica® UAS 800 to identify pathological casts and dysmorphic erythrocytes in comparison to manual microscopy. RESULTS: Erythrocyte and leukocyte analyses indicated high intra- and inter-run precisions and good correlations with the iQ200. We found that the Atellica® UAS 800 detects bacteria with higher sensitivity than the iQ200. The Atellica® UAS 800 and CLINITEK Novus® showed a high degree of conformity. We determined seven combinations of clinical cut-off values of bacteria and leukocytes for predicting urine culture outcome with sensitivity, specificity, and negative predictive values of 95%, 52%, and 93%, respectively. Using the Atellica® UAS 800, hyaline casts, erythrocyte casts, leukocyte casts, and dysmorphic erythrocytes were correctly recognized in 76%, 22%, 2%, and 39% of the samples, respectively. CONCLUSIONS: The Atellica® UAS 800 is a robust, fast, and user-friendly analyzer, which accurately quantifies erythrocytes, leukocytes, bacteria and squamous epithelial cells, and may be utilized for predicting positive urine cultures. The detection of clinically important pathological casts and dysmorphic erythrocytes proved insufficient.

Does breast milk adiponectin affect BMI and cardio-metabolic markers in childhood?

Observational studies suggest that breast-feeding is associated with a more favourable BMI and cardio-metabolic markers, but potential underlying mechanisms are unclear. As serum adiponectin has an important function in adults for glucose and lipid metabolism, we assessed 251 participants of the Prevention and Incidence of Asthma and Mite Allergy birth cohort whether breast milk adiponectin is associated with childhood BMI and cardio-metabolic markers. We measured adiponectin levels in breast milk collected around 3 months after birth of the child and subsequently obtained weight and height repeatedly up to the age of 17 years. A medical examination (including blood pressure, glycated Hb and cholesterol) was performed at the age of 8, 12 and 16 years. We used multivariable mixed models to assess the association between breast milk adiponectin and BMI and cardio-metabolic markers at these ages. In models adjusted for exact age of breast milk collection, maternal age, presence of siblings, maternal BMI, pregnancy weight gain and child's birth weight, each unit increase in log breast milk adiponectin (in ng/ml) was associated with a 0·28 lower BMI z score (95 % CI -0·56, 0·00) at 3 months. After the age of 1 year, there was a tendency towards a higher BMI z score with increased breast milk adiponectin at some ages, but this pattern was not consistent throughout childhood. There were no associations between breast milk adiponectin and any of the cardio-metabolic markers in childhood. We conclude that in our study with follow-up until 17 years of age, breast milk adiponectin has no long-term effect on BMI and cardio-metabolic health during childhood.

Additional value of a high sensitive thyroglobulin assay in the follow-up of patients with differentiated thyroid carcinoma.

OBJECTIVE: Thyroglobulin (Tg) is an excellent tumour marker, as detectable or increasing Tg levels are highly indicative of persistent or recurrent differentiated thyroid carcinoma (DTC). The clinical value of a highly sensitive (hs)-Tg assay in patients with DTC has not yet been established. The aim of this study was to investigate the additional value of unstimulated hs-Tg measurements (Tg-on) compared to stimulated IRMA-Tg measurements (Tg-off) in the follow-up of patients with DTC. DESIGN, PATIENTS, MEASUREMENTS: We retrospectively studied patients treated for DTC between 2006 and 2013 and compared hs-Tg and IRMA-Tg measurements. The study group consisted of 99 DTC patients in remission; Tg-on was measured 3 months after remnant ablation and Tg-off 6 months after ablation. RESULTS: In the study group, 44 patients showed a hs-Tg-on <0·15 µg/l (functional sensitivity); of these, 43 had an IRMA-Tg-off measurement <1·0 µg/l, resulting in a negative predictive value of 97·7% and a positive predictive value of 56·4%. CONCLUSIONS: The hs-Tg-on measurement is able to predict patients with an IRMA-Tg-off <1·0 µg/l, and therefore decreases the need for Tg stimulation after ablation.

Ovarian response to controlled ovarian hyperstimulation: what does serum FSH say?

STUDY QUESTION: Do serum FSH levels on day of hCG trigger differ between women with a poor, normal or hyper response to a fixed daily dose of 150 IU recombinant FSH (rFSH)? SUMMARY ANSWER: There is no consistent relationship between ovarian response and serum FSH levels on day of hCG trigger in a 150 IU fixed dose treatment protocol. WHAT IS KNOWN ALREADY: When ovarian response to stimulation for IVF/ICSI is suboptimal, the FSH dose is often adjusted in a subsequent cycle, thereby assuming that serum FSH levels were inadequate for optimal stimulation. STUDY DESIGN, SIZE, DURATION: Nested cohort study within a randomized controlled trial conducted at the University Medical Centre Utrecht between March 2009 and July 2011. Blood was drawn from 124 women on cycle Day 2 and on day of hCG triggering. Serum FSH level was determined by the Beckman-Coulter Unicel DXi800 chemiluminescence assay. In order to detect a difference of 2 IU/L between poor, normal and hyper responders, a total of 64 participants (16 poor, 32 normal and 16 hyper responders) would provide 80% power, assuming a standard deviation of 2 and an alpha of 0.05. PARTICIPANTS, SETTING, METHODS: Women aged ≤39 years with a regular cycle and fixed FSH dose of 150 IU. Exclusion criteria: BMI > 32 kg/m2 and >2 previous unsuccessful IVF/ICSI cycles. The primary outcome measure was serum FSH level on day of triggering. MAIN RESULTS AND THE ROLE OF CHANCE: Median [range] body weight was 70.0 kg [55.0-85.6], 68.0 kg [52.0-94] and 60.6 kg [51.0-78.0] for poor (n = 16), normal (n = 94) and hyper (n = 17) responders, respectively. Mean (SD) serum FSH levels on day of triggering were 9.5 IU/L (2.4) in poor, 10.4 IU/L (2.3) in normal and 11.5 IU/L (2.2) in hyper responders. Serum FSH levels on day of hCG in poor responders differed significantly as compared to those in hyper responders (P = 0.03). LIMITATIONS, REASONS FOR CAUTION: The number of retrieved oocytes is only minimally determined by serum FSH level on the day of hCG trigger. After correction for age, body weight, basal serum FSH and basal anti-Mullerian hormone the correlation between serum FSH level on the day of hCG and ovarian response regarding the number of retrieved oocytes disappeared. WIDER IMPLICATIONS OF THE FINDINGS: The current study shows that a poor response is not related to inadequate serum FSH levels per se. One could therefore question whether increasing the rFSH dose in women with a suboptimal response is meaningful. In women with a hyper response, however, lowering the dose of rFSH in a subsequent IVF cycle may lead to lower serum FSH levels and thereby mitigate ovarian response and improve safety of the IVF treatment. As this was not a dose-response study, future research should assess whether dose adjustments benefit the poor and hyper responder. STUDY FUNDING/COMPETING INTEREST(S): No external funds were obtained for this study. S.C.O, T.C.v.T., O.H., H.L.T., E.G.W.M.L., C.B.L. and M.J.C.E. have nothing to disclose. F.J.M.B. receives monetary compensation: member of the external advisory board for Merck Serono and Ferring, the Netherlands; educational activities for Ferring BV, the Netherlands; consultancy work for Gedeon Richter, Belgium; strategic cooperation with Roche on automated AMH assay development and research cooperation with Ansh Labs.

Role of Vitamin D in Maintaining Renal Epithelial Barrier Function in Uremic Conditions.

As current kidney replacement therapies are not efficient enough for end-stage renal disease (ESRD) treatment, a bioartificial kidney (BAK) device, based on conditionally immortalized human proximal tubule epithelial cells (ciPTEC), could represent an attractive solution. The active transport activity of such a system was recently demonstrated. In addition, endocrine functions of the cells, such as vitamin D activation, are relevant. The organic anion transporter 1 (OAT-1) overexpressing ciPTEC line presented 1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1) and vitamin D receptor (VDR), responsible for vitamin D activation, degradation and function, respectively. The ability to produce and secrete 1α,25-dihydroxy-vitamin D3, was shown after incubation with the precursor, 25-hydroxy-vitamin D3. The beneficial effect of vitamin D on cell function and behavior in uremic conditions was studied in the presence of an anionic uremic toxins mixture. Vitamin D could restore cell viability, and inflammatory and oxidative status, as shown by cell metabolic activity, interleukin-6 (IL-6) levels and reactive oxygen species (ROS) production, respectively. Finally, vitamin D restored transepithelial barrier function, as evidenced by decreased inulin-FITC leakage in biofunctionalized hollow fiber membranes (HFM) carrying ciPTEC-OAT1. In conclusion, the protective effects of vitamin D in uremic conditions and proven ciPTEC-OAT1 endocrine function encourage the use of these cells for BAK application.

A 14-year-old girl with premature ovarian insufficiency but with a positive pregnancy test.

OBJECTIVES: Childhood cancer survivors are at risk for premature ovarian insufficiency, especially after treatment with alkylating agents. The objective of this report is to highlight a case in which this phenomenon caused a false-positive pregnancy test. CASE PRESENTATION: A workup was performed in a 14-year-old girl with a positive pregnancy test. She was diagnosed with stage IV neuroblastoma of the left adrenal gland at the age of 4 years. She received extensive treatment, including alkylating agents, and had been diagnosed with premature ovarian insufficiency. An LH/hCG suppression test was performed using high dose 17 bèta-estradiol: hCG levels normalized. CONCLUSIONS: The pregnancy test was false-positive due to production of low amounts of hCG by the pituitary gland as a result of high LH concentrations following premature ovarian insufficiency. It may be helpful to perform the LH/hCG suppression test to prove pituitary origin of the hCG overproduction.

A Preliminary Analysis of Thyrotropin Measurement from Finger Stick Dried Blood Spot with an Automated High-Throughput Immunoassay Analyzer.

Background: Hyper- and hypothyroidism are prevalent in Western countries and often go unnoticed for long periods. Thyrotropin (TSH) as a biomarker of thyroid dysfunction is regularly measured in venous plasma/serum. In newborn screening for congenital hypothyroidism, TSH is measured from dried blood spots (DBSs). DBS enables minimally invasive (at-home) sampling of a small blood volume that can be sent to diagnostic laboratories by regular mail. Methods: In this study, we included 109 patients who presented to the outpatient clinic of the University Medical Center Utrecht. Capillary finger stick was used to spot blood on a filter paper card and was dried. After extraction of TSH from DBS, method comparison with venous TSH was performed on an automated high-throughput immunoassay analyzer. Additional validation steps regarding stability, effect of hematocrit (Hct), precision, and limits of blank and quantitation were conducted according to corresponding Clinical and Laboratory Standards Institute evaluation protocol. Results: Method comparison of TSH from venous plasma versus finger stick DBSs showed an R2 [95% confidence interval] = 0.988 [0.986-0.990]. This enabled correct diagnosis of hypothyrotropinemia and hypothyroidism in 12 of 14 and 6 of 7 cases, respectively, with no false positives. Furthermore, TSH from DBS was stable for at least 4 days at temperatures between -20°C and +30°C, and the maximum decrease of eluate TSH was 1.13% for 1% increase in Hct. Conclusions: TSH from DBS may be accurately measured on an automated high-throughput immunoassay analyzer and could be used to diagnose hypothyroidism and, for the first time, hypothyrotropinemia. This method, when confirmed in larger field studies, may enable individuals to engage in (at-home) sampling of blood on DBSs for telediagnostics, screening programs, patient follow-up, and medication management.

Ion suppression, reduced long-term robustness and leakage current of the spray voltage during the ionization of trichloroacetic acid; a case study with a methylmalonic acid assay.

Sample clean-up with the protein precipitation solvent trichloroacetic acid (TCA), combined with a stable isotope labeled internal standard, is widely used for the analysis of endogenous and exogenous compounds in serum and plasma with liquid chromatography-tandem mass spectrometry (LC-MS/MS). During the application of an assay for methylmalonic acid (MMA), used for routine analysis in patient care, negative long-term side effects of TCA on assay performance were observed. Step-by-step extensive troubleshooting disclosed the limitations of using TCA in MS. After running over 2000 samples with the MMA assay over a course of one year, a black coating formed between the probe and the heater that was traced to the use of TCA. The MMA assay used a C18 column with an isocratic eluent of 95% water (0.1% formic acid) as starting condition, on which TCA was more retained than MMA. Next, concentrations of 2.2% TCA in the prepared serum or plasma sample caused a drop in spray voltage during ionization into the MS. This was caused by the strong acid properties of TCA, resulting in current loss of the spray voltage between the heated electrospray ionization (HESI) needle and the union holder, which had also a grounding function. Replacing the original metal HESI needle with a custom made fussed silica HESI needle or detaching the union from the union holder, eliminated the effect of the drop in spray voltage. In conclusion, TCA can seriously affect the long-term robustness by affecting the source of the MS. We recommend the use of a very low sample injection volume, and/or shifting the mobile phase to waste when TCA is eluting, when using TCA in LC-MS/MS analysis.

Thyroid Profile in the First Three Months after Starting Treatment in Children with Newly Diagnosed Cancer.

BACKGROUND: Thyroid hormone anomalies during childhood might affect neurological development, school performance and quality of life, as well as daily energy, growth, body mass index and bone development. Thyroid dysfunction (hypo- or hyperthyroidism) may occur during childhood cancer treatment, although its prevalence is unknown. The thyroid profile may also change as a form of adaptation during illness, which is called euthyroid sick syndrome (ESS). In children with central hypothyroidism, a decline in FT4 of >20% has been shown to be clinically relevant. We aimed to quantify the percentage, severity and risk factors of a changing thyroid profile in the first three months of childhood cancer treatment. METHODS: In 284 children with newly diagnosed cancer, a prospective evaluation of the thyroid profile was performed at diagnosis and three months after starting treatment. RESULTS: Subclinical hypothyroidism was found in 8.2% and 2.9% of children and subclinical hyperthyroidism in 3.6% and in 0.7% of children at diagnosis and after three months, respectively. ESS was present in 1.5% of children after three months. In 28% of children, FT4 concentration decreased by ≥20%. CONCLUSIONS: Children with cancer are at low risk of developing hypo- or hyperthyroidism in the first three months after starting treatment but may develop a significant decline in FT4 concentrations. Future studies are needed to investigate the clinical consequences thereof.

Changes in thyroid function parameters 3 months after allogeneic and autologous hematopoietic stem cell transplantation in children.

BACKGROUND: Thyroid dysfunction (hypo- and hyperthyroidism) has been reported as a late effect after hematopoietic stem cell transplantation (HSCT) in children. Short-term effects of HSCT on thyroid function parameters are, however, unclear. METHODS: We prospectively evaluated thyroid function parameters before and 3 months after HSCT in all children (<21 years) who underwent HSCT during a 2-year period in the Princess Máxima Center, the Netherlands. RESULTS: Among 72 children, none had thyroidal hypothyroidism or hyperthyroidism 3 months after HSCT. Changes in thyroid function parameters (either aberrant thyroid-stimulating hormone [TSH] or free thyroxine [FT4] concentrations) were found in 16% before and in 10% 3 months after HSCT. Reverse triiodothyronine (rT3) was found elevated in 9.3% before and in 37% 3 months after HSCT, which could be related to poor physical condition. An individual decline in FT4 concentration of ≥20% was found in 10.5% (6/57) 3 months after HSCT. CONCLUSION: In conclusion, thyroidal hypo- and hyperthyroidism are very rare 3 months after HSCT. These results indicate that surveillance for hypo- and hyperthyroidism may start later in time. The changes in thyroid function parameters found 3 months after HSCT might reflect euthyroid sick syndrome.

Impact of Thyroglobulin and Thyroglobulin Antibody Assay Performance on the Differential Classification of DTC Patients.

CONTEXT: Measurements of thyroglobulin (Tg) and Tg antibodies are crucial in the follow-up of treated differentiated thyroid cancer (DTC) patients. Interassay differences may significantly impact follow-up. OBJECTIVE: The aim of this multicenter study was to explore the impact of Tg and Tg antibody assay performance on the differential classification of DTC patients, as described in national and international guidelines. DESIGN: Four commonly used Tg and Tg antibody assays were technically compared to reflect possible effects on patients with DTC follow-up. Storage stability at different storage temperatures was also investigated for LIAISON® and Kryptor assays, as this is an underexposed topic in current literature. RESULTS: B.R.A.H.M.S. assays yield approximately 50% lower Tg values over the whole range compared to the DiaSorin and Roche assays investigated. These differences between assays may result in potential misclassification in up to 7% of patients if fixed cutoffs (eg, 1 ng/mL) are applied. Poor correlation was also observed between the Tg antibody assays when the method-specific upper limits of normal are used as cutoffs. Storage of Tg and Tg antibodies was possible for 3 to 4 weeks at -20°C and -80°C. Calibration of the assays, however, was found to be crucial for stable results over time. CONCLUSIONS: Technical aspects of Tg and Tg antibody assays, including interassay differences, calibration and standardization, and cutoff values, may have a significant clinical impact on the follow-up of DTC patients.

Clinical Applicability of Low Levels of Thyroglobulin Autoantibodies as Cutoff Point for Thyroglobulin Autoantibody Positivity.

BACKGROUND: Thyroglobulin (Tg) is an established tumor marker in differentiated thyroid carcinoma (DTC). However, Tg assays can be subject to interference by autoantibodies against Tg (TgAbs). No clinical consensus exists on the cutoff value of TgAb positivity and its relationship to Tg assay interference. The aims of this study were to investigate the most applicable cutoff value for TgAb positivity in clinical practice and to evaluate whether tumor characteristics differ between TgAb+ and TgAb- patients during ablation therapy using the manufacturer's cutoff (MCO) and institutional cutoff (ICO). METHODS: This single-center cohort study included 230 DTC patients diagnosed between January 2006 and December 2014. Serum Tg and TgAbs were measured with the Tg-IRMA (Thermo Fisher Scientific) and ARCHITECT Anti-Tg (Abbott Laboratories) assays. Patients were divided into TgAb- and TgAb+ based on the limit of detection (LoD; ≥0.07 IU/mL), functional sensitivity (FS; ≥0.31 IU/mL), MCO (≥4.11 IU/mL), and ICO (≥10 IU/mL). RESULTS: All patients were TgAb+ based on the LoD; one patient was negative on FS. Fifty-five (23.9%) and 34 (14.8%) patients had TgAbs above the MCO and ICO, respectively. Histology, presence of multifocality, tumor-node-metastasis, and American Thyroid Assocation risk stratification did not differ between TgAb- and TgAb+ patients using MCO and ICO during ablation. CONCLUSIONS: This study supports the use of a higher cutoff value than that of the FS for TgAb positivity in clinical settings. The LoD and FS are too sensitive to discriminate TgAb positivity and negativity in DTC patients during ablation therapy. The presence of TgAbs during ablation is not related to tumor characteristics and risk profile. This implies that TgAb positivity should not be considered a separate risk factor.

Prediagnostic Serum Vitamin D Levels and the Risk of Crohn's Disease and Ulcerative Colitis in European Populations: A Nested Case-Control Study.

Background: A low vitamin D status has been put forward as a potential risk factor for the development of inflammatory bowel disease (IBD). This study investigated the association between prediagnostic circulating vitamin D concentrations and dietary intakes of vitamin D, and the risk of Crohn's disease (CD) and ulcerative colitis (UC). Methods: Among 359,728 participants of the European Prospective Investigation into Cancer and Nutrition cohort, individuals who developed CD or UC after enrollment were identified. Each case was matched with2 controls by center, gender, age, date of recruitment, and follow-up time. At cohort entry, blood samples were collected and dietary vitamin D intakes were obtained from validated food frequency questionnaires. Serum 25-hydroxyvitamin D levels were measured using liquid chromatography-tandem mass spectrometry. Conditional logistic regression was performed to determine the odds of CD and UC. Results: Seventy-two participants developed CD and 169 participants developed UC after a median follow-up of 4.7 and 4.1 years, respectively. Compared with the lowest quartile, no associations with the 3 higher quartiles of vitamin D concentrations were observed for CD (p trend = 0.34) or UC (p trend = 0.66). Similarly, no associations were detected when serum vitamin D levels were analyzed as a continuous variable. Dietary vitamin D intakes were not associated with CD (p trend = 0.39) or UC (p trend = 0.83). Conclusions: Vitamin D status was not associated with the development of CD or UC. This does not suggest a major role for vitamin D deficiency in the etiology of IBD, although larger studies are needed to confirm these findings.