Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia.

BACKGROUND: Recent guidelines recommend establishing a local reference interval (RI) for thyroid function. We aimed to establish trimester-specific RIs for thyrotropin (TSH) and free thyroxine (FT4) in a cohort of healthy pregnant women in Catalonia (Spain). METHODS: A prospective observational study was conducted with 332 healthy pregnant women, from the first trimester (1T) to delivery. TSH was measured using an Architect® immunoassay (Abbott) and FT4 by two immunoassays, Architect® (Abbott) and Cobas® (Roche), in the three trimesters. FT4 was also measured by liquid chromatography mass spectrometry (LC/MS/MS) in the 1T. RESULTS: TSH (µUI/mL) increased throughout pregnancy (1T: 0.03-3.78; 2T: 0.51-3.53; 3T: 0.50-4.32; p < 0.0001) and FT4 (pmol/L) progressively decreased (Architect® 1T: 10.42-15.96; 2T: 8.37-12.74; 3T: 8.24-12.49; p < 0.0001; and Cobas®: 1T: 11.46-19.05; 2T: 9.65-14.67; 3T: 8.88-14.54; p < 0.0067). The FT4 RI during 1T determined LC/MS/MS was 8.75-18.27. Despite the 1T FT4 results measured by LC/MS/MS and with the two immunoassays being significantly correlated, the results obtained by the three methods were found to be non-interchangeable. CONCLUSIONS: We established trimester-specific RIs for TSH and for FT4 with immunoassays in our population. We also validated the 1T FT4 using LC/MS/MS to confirm the results of FT4 lower than the 2.5th percentile or higher than the 97.5th percentile.

The laboratory in the multidisciplinary diagnosis of differences or disorders of sex development (DSD): III) Biochemical and genetic markers in the 46,XYIV) Proposals for the differential diagnosis of DSD.

Objectives: 46,XY differences/disorders of sex development (DSD) involve an abnormal gonadal and/or genital (external and/or internal) development caused by lack or incomplete intrauterine virilization, with or without the presence of Müllerian ducts remnants. Content: Useful biochemical markers for differential diagnosis of 46,XY DSD include hypothalamic-pituitary-gonadal hormones such as luteinizing and follicle-stimulating hormones (LH and FSH; in baseline or after LHRH stimulation conditions), the anti-Müllerian hormone (AMH), inhibin B, insulin-like 3 (INSL3), adrenal and gonadal steroid hormones (including cortisol, aldosterone, testosterone and their precursors, dihydrotestosterone and estradiol) and the pituitary ACTH hormone. Steroid hormones are measured at baseline or after stimulation with ACTH (adrenal hormones) and/or with HCG (gonadal hormones). Summary: Different patterns of hormone profiles depend on the etiology and the severity of the underlying disorder and the age of the patient at diagnosis. Molecular diagnosis includes detection of gene dosage or copy number variations, analysis of candidate genes or high-throughput DNA sequencing of panels of candidate genes or the whole exome or genome. Outlook: Differential diagnosis of 46,XX or 46,XY DSD requires a multidisciplinary approach, including patient history and clinical, morphological, imaging, biochemical and genetic data. We propose a diagnostic algorithm suitable for a newborn with DSD that focuses mainly on biochemical and genetic data.

The laboratory in the multidisciplinary diagnosis of differences or disorders of sex development (DSD): I) Physiology, classification, approach, and methodologyII) Biochemical and genetic markers in 46,XX DSD.

Objectives: The development of female or male sex characteristics occurs during fetal life, when the genetic, gonadal, and internal and external genital sex is determined (female or male). Any discordance among sex determination and differentiation stages results in differences/disorders of sex development (DSD), which are classified based on the sex chromosomes found on the karyotype. Content: This chapter addresses the physiological mechanisms that determine the development of female or male sex characteristics during fetal life, provides a general classification of DSD, and offers guidance for clinical, biochemical, and genetic diagnosis, which must be established by a multidisciplinary team. Biochemical studies should include general biochemistry, steroid and peptide hormone testing either at baseline or by stimulation testing. The genetic study should start with the determination of the karyotype, followed by a molecular study of the 46,XX or 46,XY karyotypes for the identification of candidate genes. Summary: 46,XX DSD include an abnormal gonadal development (dysgenesis, ovotestes, or testes), an androgen excess (the most frequent) of fetal, fetoplacental, or maternal origin and an abnormal development of the internal genitalia. Biochemical and genetic markers are specific for each group. Outlook: Diagnosis of DSD requires the involvement of a multidisciplinary team coordinated by a clinician, including a service of biochemistry, clinical, and molecular genetic testing, radiology and imaging, and a service of pathological anatomy.

El laboratorio en el diagnóstico multidisciplinar del desarrollo sexual anómalo o diferente (DSD): III) Marcadores bioquímicos y genéticos en los 46,XY IV) Propuestas para el diagnóstico diferencial de los DSD.

Objetivos: El desarrollo sexual anómalo o diferente (DSD) con cariotipo 46,XY incluye anomalías en el desarrollo gonadal y/o genital (externo y/o interno). Contenido: Los marcadores bioquímicos útiles para el diagnóstico diferencial de los DSD con cariotipo 46,XY incluyen las hormonas del eje hipotálamo-hipófiso gonadal como son las gonadotropinas LH y FSH (en condiciones basales o tras la estimulación con LHRH), la hormona anti-Mülleriana, la inhibina B, el factor insulinoide tipo 3 y las hormonas esteroideas de origen suprarrenal (se incluirá la hormona hipofisaria ACTH) y testicular (cortisol, aldosterona y sus precursores, testosterona y sus precursores, dihidrotestosterona y estradiol). Las hormonas esteroideas se analizarán en condiciones basales o tras la estimulación con ACTH (hormonas adrenales) y/o con HCG (hormonas testiculares). Los patrones de variación de las distintas hormonas dependerán de la causa y la edad de cada paciente. El diagnóstico molecular debe incluir el análisis de un gen candidato, un panel de genes o el análisis de un exoma completo. Perspectivas: El diagnóstico diferencial de los DSD con cariotipos 46,XX ó 46,XY debe ser multidisciplinar, incluyendo los antecedentes clínicos, morfológicos, de imagen, bioquímicos y genéticos. Se han elaborado numerosos algoritmos diagnósticos.

Laparoscopic sleeve gastrectomy induces molecular changes in peripheral white blood cells.

BACKGROUND & AIMS: Peripheral white blood cells (PWBC) may allow for the development of obesity biomarkers. We aimed to investigate the existence of gene expression and DNA methylation changes in PWBC after a very low calorie diet (VLCD) followed by a laparoscopic sleeve gastrectomy (LSG), and its correlation with surgical outcomes. METHODS: From July 2013 to June 2014, 35 consecutive bariatric patients and 33 healthy lean volunteers were recruited. Molecular data was obtained once on the control group and at 3 different times on the LSG group: 1) at baseline; 2) after 2 weeks of VLCD, right before LSG; and 3) 6 months after LSG. The expression of 12 genes in PWBC was analyzed by quantitative real-time polymerase chain reaction: ghrelin (GHRL), visfatin (NAMPT), insulin receptor substrate 1 (IRS1), fat mass and obesity-related gene (FTO), leptin (LEP), peroxisome proliferator-activated receptor gamma (PPARG), adiponectin (ADIPOQ), fatty acid synthase (FASN), melanocortin 4 receptor (MC4R), fas cell surface death receptor (FAS), tumor necrosis factor alpha (TNF) and chemokine (C-C motif) ligand 2 (CCL2). Moreover, DNA methylation of GHRL, NAMPT and FAS promoters was analyzed in PWBC by bisulfite pyrosequencing. RESULTS: Seven genes (GHRL, NAMPT, IRS1, FTO, FAS, TNF and CCL2) had detectable expression in PWBC. FTO expression at baseline was lower in patients than in controls (p = 0.042), equalizing after LSG. In patients, FAS expression decreased after VLCD (p = 0.01) and stayed low after LSG (p = 0.015). Also, CCL2 expression decreased 50% after LSG compared to pre-surgical levels (p = 0.016). All studied CpG sites in the GHRL gene promoter followed a consistent pattern of DNA methylation/demethylation. No direct correlation between these molecular changes and surgical outcomes was found at 1-year follow-up. CONCLUSIONS: FTO expression increased and FAS and CCL2 expression decreased in PWBC after LSG. Molecular changes did not correlate with surgical outcomes.

Biochemical following-up of treated acromegaly. Limitations of the current determinations of IGF-I and perspective.

Acromegaly is a rare disease caused by excess growth hormone (GH) secretion leading to an insulin-like growth factor-1 (IGF-I) which is the major mediator of GH action. Biochemical diagnosis of GH excess is accomplished by the combined measurement of baseline serum IGF-I concentration and the response of GH on an oral glucose tolerance test (OGTT). Several drawbacks regarding the interpretation of biochemical tests that include measurement of GH have been widely described in the literature, including different protocols for obtaining serum samples, great differences in the results obtained by different immunoassays, different cut-off points used to differentiate the normal status of the hypersecretion of GH. Clinical guidelines related to the diagnosis and management of patients with acromegaly state that "normal" IGF-I concentrations, (within an established age- and sex- reference range), excludes the diagnosis of active acromegaly, and mean disease control in patients who have received treatment. But many factors may exert influence over IGF-I measurement or interpretation and limit its value as a biological marker of disease activity. Major drawbacks of IGF-I measurements derive both from its own physiology, to the divergences in results obtained from different biochemical methods used for their quantification, to the heterogeneous ways of expressing the results obtained and to the lack of uniformity of the cut-offs to define treatment effectiveness. All these issues make it difficult to compare the results obtained by different authors. We will focus on the issues regarding the measurement and interpretation of IGF-I concentrations in the management of acromegaly patients.

Measured free 25-hydroxyvitamin D in healthy children and relationship to total 25-hydroxyvitamin D, calculated free 25-hydroxyvitamin D and vitamin D binding protein.

BACKGROUND: vitamin D deficiency in children is still a global health problem. Measuring free 25-hydroxyvitamin D concentrations could provide a better estimate of the vitamin D status than total 25-hydroxyvitamin D (25(OH)D) levels. OBJECTIVE: To assess the relationship between measured free vitamin D (m-f25(OH)D) and calculated free 25(OH)D (c-f25(OH)D), total 25(OH)D, intact parathyroid hormone (iPTH) and other markers of phosphocalcic metabolism. To establish serum m-f25(OH)D concentrations corresponding to a total 25(OH)D > 50 nmol/L which is accepted as vitamin D-sufficiency status in children. DESIGN: Prospective cohort study. SETTING: January and February 2017 in a Mediterranean population. PATIENTS: healthy children. MEASUREMENTS: m-f25(OH)D and vitamin D binding protein (VDBP) by ELISA. Free 25(OH)D was calculated using the formula described by Bikle. RESULTS: m-f25(OH)D directly correlated with total 25(OH)D (r:0.804,p < .001), serum calcium (r:0.26,p:0.035), and c-f25(OH)D (r:0.553,p:0.016); and inversely with iPTH (r:-0.374, p:0.002), alkaline phosphatase (r:-0.28, p:0.026), and age (r:-0.289, p:0.018). Total 25(OH)D correlated with the same parameters as m-f25(OH)D except for serum calcium. However, c-f25(OH)D correlated only with total 25(OH)D and VDBP, both included in the calculation formula. Multiple regression analysis showed that m-f25(OH)D variations were independently explained by calcium (ß:0.156, p:0.026) and total 25(OH)D (ß:0.043, p < .001). The optimal m-f25(OH)D cut-off for discriminating between insufficient and sufficient total 25(OH)D was >9.8 pmol/L (Area Under Curve (AUC): 0.897 (95% confidence interval (CI): (0.798-0.958); p < .001; sensitivity:72.7% (95%CI: 49.8-89.3); specificity: 95.5% (95%CI: 84.5-99.4)). CONCLUSIONS: Directly measured free vitamin D correlated better with markers of phosphocalcic metabolism than total 25(OH)D and c-f25(OH)D in a population of healthy children.

Evaluation of Vitamin and Trace Element Requirements after Sleeve Gastrectomy at Long Term.

BACKGROUND: Nutritional deficiencies are common after bariatric surgery, but data are scarce after sleeve gastrectomy (SG) at long term. METHODS: We performed a prospective nutritional status evaluation before and at 2 and 5 years after SG in morbid obese patients receiving mulvitamin and mineral supplementation at a Spanish university hospital. One hundred seventy-six patients (49.3 ± 9.1 years and 46.7 ± 7.4 kg/m2) were evaluated; 51 of them were followed during 5 years. Anthropometric, compliance supplementation intake, and micronutrient evaluation were performed. RESULTS: Baseline concentrations were below normal values for 25(OH) vitamin D (73%), folic acid (16.5%), cobalamin (6.9%), pyridoxine (12%), thiamine (3.4%), and copper (0.5%). Anemia was found in 23%. In 49% of the subjects, at least one micronutrient deficiency was found at 2 years after SG. Vitamin D deficiency persisted at 2 and 5 years higher than 30% of patients. Frequencies of deficiencies for folic acid, B12, B6, and B1 vitamins decreased significantly after 2 years with normalization at 5 years. Copper deficiency increased between 1 and 2 years and it persisted at 5 years after SG. Vitamin supplementation compliance decreased progressively from the first year after surgery (94.8 to 81% at 2 years and to 53% 5 years after surgery). CONCLUSIONS: Vitamin D deficiency is the most prevalent long-term nutritional deficiency after SG. About half of patients show some micronutrient deficiency at medium long term, despite supplementation. A proactive follow-up is required to ensure a personalized and adequate supplementation in all surgically treated obese patients including those in which SG has been performed.

Chronic proton pump inhibition therapy in the diagnostic accuracy of serum pepsinogen I and gastrin concentrations to identify pernicious anaemia.

BACKGROUND: Chronic use of proton pump inhibitors (PPIs) leads to increases in gastrin and pepsinogen-I serum concentrations. AIM: To asses if chronic treatment with PPIs has an effect on serum gastrin and pepsinogen-I concentrations for the diagnosis of pernicious anaemia (PA). MATERIALS AND METHODS: Serum gastrin and pepsinogen-I were measured in 38 patients with PA and 74 without PA (controls); 17/38 PA patients and 36/74 controls were treated with PPIs. Receiver Operating Curves (ROC) were used to compare diagnostic accuracy of gastrin and pepsinogen-I for PA in patients under chronic treatment with PPIs and in untreated patients. RESULTS: PPI treatment increased pepsinogen-I in patients and in controls, while gastrin increased only in controls. In untreated patients, a pepsinogen-I <8.3ng/mL had 95.2% sensitivity and 100% specificity, whereas a gastrin >115pg/mL had 100% sensitivity and 92.11% specificity for PA diagnosis. In PPI-treated patients, a pepsinogen I<24.1ng/mL had a lower sensitivity (82.4%) but retained 100% specificity, however the best cut-off point for gastrin, 610pg/mL, had a very low sensitivity (58%). CONCLUSIONS: PPI chronic treatment decreased the diagnostic accuracy for the studied biomarkers, particularly of gastrin. In PPI-treated patients, serum pepsinogen-I concentrations >24.1ng/mL allowed rejecting a PA diagnosis with 100% specificity.

Variability in adherence to rhGH treatment: Socioeconomic causes and effect on children's growth.

BACKGROUND: In children with growth disorders, mean final height is associated to poor adherence to Growth Hormone therapy. The primary goal of this study is to identify patients who do not adhere to GH therapy and determine the influence of adherence in response to the treatment. The role of serum IGF-I and influence of socio-economic factors on the therapeutic adherence will also be evaluated. METHODS: 158 children under treatment with rhGH were included in the study. Age, gender, etiology, Tanner stage, duration of treatment, growth rate, IGF-I serum values, daily dose, and annual rhGH dose data were collected. Adherence to therapy was defined as moderate-to-poor when the patient had taken less than 92% of the prescribed medication. A subgroup of 106 patients completed a questionnaire to assess social and environmental effects. RESULTS: Moderate-to-poor adherence to rhGH treatment was determined in 33.5% of study patients. A decrease in adherence was associated to treatment duration (p=0.001). A significant correlation was determined between adherence and height velocity (p=0.002) and IGF-I (p<0.0001) levels. Adherence rates were associated to the mother's educational level (p=0.007). CONCLUSION: Poor adherence to GH therapy was observed in one-third of study patients, resulting in suboptimal growth. IGF-I levels can be helpful to identify patients with poor adherence to GH medication. Physicians should pay special attention to certain characteristics of the patient and their environment, and encourage desirable therapeutic compliance.

Sodium interference in the determination of urinary aldosterone.

OBJECTIVES: Primary hyperaldosteronism (PHA) is one of the most common endocrine forms of secondary hypertension. Among the most used confirmatory tests for PHA is urinary aldosterone determination after oral sodium loading test. The primary aim of our study was to investigate if sodium concentrations interfere with urinary aldosterone in an automated competitive immunoassay (Liaison®) as well as to verify the manufacturer's specifications. DESIGN AND METHODS: 24-hr urine samples were collected and stored frozen until assayed. Two pools at low and high aldosterone concentrations were prepared. Verification of performance for precision was tested according to Clinical and Laboratory Standards Institute (CLSI) document EP15-A2 and interference with increasing concentrations of NaCl according to CLSI EP7-A2. RESULTS: The assay met the quality specifications according to optimal biological variation. Our results show that sodium concentrations up to 200mmol/L do not interfere on urinary aldosterone quantification, but sodium concentrations above 486mmol/L negatively interfere with the test. CONCLUSIONS: The Liaison® automated method is useful for aldosterone determination in the PHA confirmatory test, but interferences with NaCl may occur. It is therefore recommended to determine urinary NaCl before measuring urinary aldosterone to avoid falsely low results.

Disminución de la respuesta eritropoyética en pacientes con anorexia nerviosa y anemia / Blunted erythropoietic response in the anemia of anorexia nervosa

Fundamento y objetivo: La causa o causas de la anemia que acompaña a la anorexia nerviosa (AN) no ha sido establecida, pero no parece relacionarse con deficiencias nutricionales ni cambios medulares. El objetivo de este trabajo fue evaluar la producción de eritropoyetina (EPO) en respuesta a la anemia en un pequeño grupo de pacientes con AN y anemia. Pacientes y métodos: Los niveles de EPO en muestras de suero de 41 mujeres con AN (11 con anemia y 30 sin alteraciones en los parámetros de la serie eritroide) se compararon con la respuesta observada en un grupo de pacientes de peso normal con anemia. Resultados: Las concentraciones de EPO en pacientes con AN anémicas fueron mayores que en las no anémicas: 20,63 mU/ml (4,04 a 28,46) frente a 8,7 mU/ml (3,9 a 20,93), p = 0,0088, pero el aumento de EPO fue menor de lo esperado (27,85 mU/ml [17,7 a 118,9]), p = 0,014. La correlación entre el IMC y la diferencia entre la EPO y la EPO esperada es inversa. Conclusiones: Una producción inadecuada de EPO puede explicar en parte la anemia en la AN. Son necesarios más estudios para investigar la causa de esta respuesta (AU)

Background and objective: The cause of the anemia in anorexia nervosa (AN) has not been fully ascertained. Ferritin, folate and cobalamin values are usually within normal ranges. Anemia does not have a relationship with bone marrow changes and erythropoietin (EPO) levels have not been investigated. The objective of this study was to evaluate the EPO response in a small group of AN patients. Patients and methods: EPO levels were measured in serum samples of 41 female AN patients (11 with anemia, and 30 with normal blood cell count). The adequacy of EPO response was assessed by comparing the increase observed in a group of normal weight patients with anemia. Results: EPO concentrations in anemic AN patients were higher than in non-anemic: 20.63 mU/mL (4.04-28.46) vs 8.7 mU/mL (3.9-20.93), P = .0088, but the increase in EPO was lower than expected (27.85 mU/mL [17.7-118.9]), P = .014. BMI and the difference between actual and expected EPO were inversely correlated. Conclusions: Inadequate EPO response may partly explain anemia in AN, but further studies are necessary (AU)

Metabolic Syndrome Predicts Refractoriness to Intravenous Thrombolysis in Acute Ischemic Stroke.

BACKGROUND: Metabolic syndrome (MetS) has been associated with higher resistance to clot lysis at 24 hours after tissue plasminogen activator (tPA) administration in patients with acute ischemic stroke. We aimed to test this hypothesis at earlier time points, when neurointerventional rescue procedures may still be indicated to achieve arterial recanalization. METHODS: This is a prospective and observational study in consecutive stroke patients with MCA occlusion treated with IV tPA. MetS was diagnosed following the unified criteria of the last Joint Interim Statement 2009 participating several major organizations. The primary outcome variable was resistance to thrombolysis, defined as the absence of complete middle cerebral artery recanalization 2 hours after tPA bolus assessed by transcranial color-coded duplex or when rescue mechanical thrombectomy after IV tPA was required. Secondary outcome variables were dramatic neurological improvement (decrease in ≥10 points, or a National Institutes of Health Stroke Scale [NIHSS] score of 0-1 at 24 hours), symptomatic intracerebral hemorrhage following European-Australasian Acute Stroke Study II criteria, infarct volume at 24 hours (calculated by using the formula for irregular volumes, ABC/2), and good outcome (modified Rankin Scale score < 3) at 3 months. RESULTS: A total of 234 patients (median baseline NIHSS score 16 [10-20]) were included and 146 (62.4%) fulfilled MetS criteria. After multivariate analysis, MetS emerged as an independent predictor of resistance to thrombolysis (odds ratio = 2.2 [1.3-4.2], P = .01) and absence of dramatic neurological improvement (odds ratio = .5 [.28-.97], P = .04). In addition, MetS conferred poorer functional outcome, higher symptomatic intracerebral hemorrhage rate, and increased infarct volume, although these associations disappeared after adjustment for covariates. CONCLUSIONS: MetS predicts patients with middle cerebral artery occlusion refractory to early clot dissolution after IV tPA. This finding may help in acute clinical decision-making.

Breaking Therapeutic Inertia in Type 2 Diabetes: Active Detection of In-Patient Cases Allows Improvement of Metabolic Control at Midterm.

Type 2 diabetes (T2D) exists in 25-40% of hospitalized patients. Therapeutic inertia is the delay in the intensification of a treatment and it is frequent in T2D. The objectives of this study were to detect patients admitted to surgical wards with hyperglycaemia (HH; fasting glycaemia > 140 mg/dL) as well as those with T2D and suboptimal chronic glycaemic control (SCGC) and to assess the midterm impact of treatment modifications indicated at discharge. A total of 412 HH patients were detected in a period of 18 months; 86.6% (357) had a diagnosed T2D. Their preadmittance HbA1c was 7.7 ± 1.5%; 47% (189) had HbA1c ≥ 7.4% (SCGC) and were moved to the upper step in the therapeutic algorithm at discharge. Another 15 subjects (3.6% of the cohort) had T2D according to their current HbA1c. Ninety-four of the 189 SCGC patients were evaluated 3-6 months later. Their HbA1c before in-hospital-intervention was 8.6 ± 1.2% and 7.5 ± 1.2% at follow-up (P < 0.004). Active detection of hyperglycaemia in patients admitted in conventional surgical beds permits the identification of T2D patients with SCGC as well as previously unknown cases. A shift to the upper step in the therapeutic algorithm at discharge improves this control. Hospitalization is an opportunity to break therapeutic inertia.

[Blunted erythropoietic response in the anemia of anorexia nervosa]. / Disminución de la respuesta eritropoyética en pacientes con anorexia nerviosa y anemia.

BACKGROUND AND OBJECTIVE: The cause of the anemia in anorexia nervosa (AN) has not been fully ascertained. Ferritin, folate and cobalamin values are usually within normal ranges. Anemia does not have a relationship with bone marrow changes and erythropoietin (EPO) levels have not been investigated. The objective of this study was to evaluate the EPO response in a small group of AN patients. PATIENTS AND METHODS: EPO levels were measured in serum samples of 41 female AN patients (11 with anemia, and 30 with normal blood cell count). The adequacy of EPO response was assessed by comparing the increase observed in a group of normal weight patients with anemia. RESULTS: EPO concentrations in anemic AN patients were higher than in non-anemic: 20.63mU/mL (4.04-28.46) vs 8.7mU/mL (3.9-20.93), P=.0088, but the increase in EPO was lower than expected (27.85mU/mL [17.7-118.9]), P=.014. BMI and the difference between actual and expected EPO were inversely correlated. CONCLUSIONS: Inadequate EPO response may partly explain anemia in AN, but further studies are necessary.

Lack of transferability between two automated immunoassays for serum IGF-I measurement.

BACKGROUND: IGF-I is a clinically relevant protein in the diagnosis and monitoring of treatment of growth disor- ders. The Growth Hormone Research Society and the International IGF Research Society have encouraged the adoption of a universal calibration for immunoassays to improve standardization of IGF-I measurements, but currently commercial assays are calibrated either against the old WHO IRR 87/518 or the new WHO 02/254. We compared two IGF-I immunochemiluminescent assays: IMMULITE® 2000 (Siemens) and LIAISON® (DiaSorin), which differ in their standardization, and verified their precision according to quality specifications based on biological variation and their linear range. METHODS: 62 patient serum samples were analyzed for both assays and compared according to standards of the Clinical and Laboratory Standards Institute (CLSI), EP9-A2-IR. Precision was verified according to CLSI EP15- A2. Optimal coefficient of variation (CVo) and desirable coefficient of variation (CVd) for IGF-I assays were calculated as quality specifications based on the biological variability, in order to assess if the interassay analytical CV (CVa1) in the two methods were appropriate. Two dilution series using the 1st WHO International Standard (WHO IS) for IGF-I 02/254 were used to verify and compare the linearity range. RESULTS: The regression analysis showed constant and proportional differences for serum samples (slope b = 0.8115 (CI 95% CI; 0.7575-0.8556); intercept a = 33.6873 (95% CI: 23.3613-44.0133) between assays and similar pro- portional differences for WHO IS 02/254 standard dilutions series (slope b = 0.8024 (CI 95% CI; 0.7560-0.8616); intercept a = 6.9623 (95% CI: -2.0819-18.4383) between assays. Within-laboratory coefficients of variation for low and high levels were 2.82% and 3.80% for IMMULITE® 2000 and 3.58% and 2.14% for LIAISON®, respecttively. CONCLUSIONS: IGF-I concentrations measured by both assays are not transferable. The results emphasize the need to express IGF-I concentrations in standard deviation score (SDS) according to a matched normal population of the same age and gender. Within-laboratory precision in both methods met quality specifications derived from biological variation.

IGF1 modifications after bariatric surgery in morbidly obese patients: potential implications of nutritional status according to specific surgical technique.

OBJECTIVES: IGF1 is decreased in morbidly obese (MO) patients and its changes after bariatric surgery weight loss (WL) are not well known. The aim of this study was to analyse IGF1 modifications in MO patients after WL and its relationship to ghrelin and to different types of surgeries. DESIGN: Retrospective follow-up study at the University Medical Center. METHODS: One hundred and nine MO patients (age 44.19.3, BMI 51.748.75KG/M(2)) were evaluated at baseline and 1 year after surgery: 28 sleeve gastrectomy (SG), 31 distal modified (m), and 50 ringed (r) Roux-en-Y gastric bypass (RYGBP) surgery. Changes in IGF1, IGFBP3, ratio IGF1:IGFBP3, and ghrelin were evaluated 1 year after surgery. RESULTS: Baseline prevalence of low IGF1 (defined by s.d. IGF1<-2) was 22%, and %WL 1 year after surgery was 34.9±8.9%. There was a significant decrease in IGFBP3 in all the procedures, an increase in IGF1:IGFBP3 ratio in rRYGBP and SG, but total IGF1 only increased significantly in SG. Albumin concentrations decreased in mRYGBP, did not change in rRYGBP, but increased in SG after surgery. Total ghrelin concentrations increased after both RYGBPs and decreased after SG (P<0.05 in all cases). The prevalence of low IGF1 decreased in SG (28.6 vs 10.1%, P=0.03) and did not change in RYGPBP techniques. The %albumin change was the only dependent variable associated with the % total IGF1 change. CONCLUSIONS: Recovery of low IGF1 after bariatric surgery was specifically related to the albumin modifications induced by surgery and was not related to ghrelin modifications.