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The proper clinical approach to a wide range of disorders relies on the availability of accurate, reproducible laboratory results for sexual steroids measured using methods with a high specificity and sensitivity. The chemiluminescent immunoassays currently available have analytical limitations with significant clinical implications. This position statement reviews the current limitations of laboratory techniques for the measurement of estradiol and testosterone and their impact on diverse clinical scenarios. A set of recommendations are provided to incorporate steroid hormone analysis by mass spectrometry in national health systems. International societies have recommended this methodology for a decade., Competing Interests: Competing interests: Authors state no conflict of interest., (© 2023 the author(s), published by De Gruyter, Berlin/Boston.)

Background: The diagnosis of hepatitis B virus (HBV) infection requires HBV DNA testing and serologic testing for detection of the surface antigen (HBsAg) and the hepatitis B core antibody (anti-HBc). There is a population of patients with occult HBV infection (OBI), which is not detected by HBsAg or HBV DNA quantification in blood, despite the presence of active replication in the liver., Scope: This document provides a definition of OBI and describes the diagnostic techniques currently used. It also addresses the detection of patients with risk factors and the need for screening for OBI in these patients., Summary: Correct diagnosis of OBI prevents HBV reactivation and transmission. Diagnosis of OBI is based on the detection of HBV DNA in patients with undetectable HBsAg in blood., Perspectives: A high number of patients with OBI may remain undiagnosed; therefore, screening for OBI in patients with factor risks is essential. For a correct diagnosis of OBI, it is necessary that new markers such as ultrasensitive HBsAg are incorporated, and a more comprehensive marker study is performed by including markers such as cccDNA., Competing Interests: Competing interests: Authors state no conflict of interest., (© 2022 the author(s), published by De Gruyter, Berlin/Boston.)

Introduction: Abnormal liver biochemistry is not a rare finding in the context of SARS-CoV-2 infection, regardless of patients having pre-existing chronic disease or not., Content: This review examines the current body of knowledge on the relationship between COVID-19 and liver injury, which is frequently found in this setting., Summary: Although the pathogenesis of liver injury is not fully understood, it has been suggested to be the result of a combination of multiple factors. These include direct injury caused by the virus, immune system hyperactivation, ischemic and drug-induced injury. The prognostic valor of these alterations is also the subject of intense research. Due to their potential impact, these alterations require proper management and treatment, especially in patients with chronic liver disease or liver transplant recipients., Outlook: Some aspects associated with liver injury during COVID-19, especially in severe presentations, are not well understood. Studies assessing the clinical impact of COVID-19 on the healthy or diseased liver may help adjust treatment and immunization guidelines to the profile of the patient., Competing Interests: Competing interests: Authors state no conflict of interest., (© 2022 Sergio Salgüero Fernández et al., published by De Gruyter, Berlin/Boston.)

Elevated plasma bilirubin levels are a frequent clinical finding. It can be secondary to alterations in any stage of its metabolism: (a) excess bilirubin production (i.e., pathologic hemolysis); (b) impaired liver uptake, with elevation of indirect bilirubin; (c) impaired conjugation, prompted by a defect in the UDP-glucuronosyltransferase; and (d) bile clearance defect, with elevation of direct bilirubin secondary to defects in clearance proteins, or inability of the bile to reach the small bowel through bile ducts. A liver lesion of any cause reduces hepatocyte cell number and may impair the uptake of indirect bilirubin from plasma and diminish direct bilirubin transport and clearance through the bile ducts. Various analytical methods are currently available for measuring bilirubin and its metabolites in serum, urine and feces. Serum bilirubin is determined by (1) diazo transfer reaction, currently, the gold-standard; (2) high-performance liquid chromatography (HPLC); (3) oxidative, enzymatic, and chemical methods; (4) direct spectrophotometry; and (5) transcutaneous methods. Although bilirubin is a well-established marker of liver function, it does not always identify a lesion in this organ. Therefore, for accurate diagnosis, alterations in bilirubin concentrations should be assessed in relation to patient anamnesis, the degree of the alteration, and the pattern of concurrent biochemical alterations., Competing Interests: Competing interests: Authors state no conflict of interest., (© 2021 Armando Raúl Guerra Ruiz et al., published by De Gruyter, Berlin/Boston.)

Metabolic-associated fatty liver disease (MAFLD) is defined as fat accumulation in the liver in the presence of metabolic alterations. This disorder is generally asymptomatic and may progress to severe liver disease, which are linked to inflammation and/or fibrosis. MAFLD has a high prevalence (26%) and therefore a considerable number of patients are at high risk of having advanced liver disease. This document provides an overview of the most relevant serological markers in the characterization and diagnosis of MAFLD. An example is provided of a routine diagnostic algorithm that incorporates serological testing. A range of useful serological scores are currently available for the management of MAFLD patients, especially for the stratification of patients at risk of fibrosis. A large proportion of the population is at risk of developing severe liver disease. The integration of non-invasive serological markers in the stratification of patients at risk for liver fibrosis may contribute to improve the control and management of MAFLD patients., (© 2021 Armando R. Guerra-Ruiz et al., published by De Gruyter, Berlin/Boston.)

Background: Serum estradiol (E2) levels may be used in the diagnostic and/or monitoring of a broad variety of clinical conditions. The aims of this study were to evaluate the Siemens enhanced estradiol assay (eE2) on Atellica IM 1600 (Siemens Healthineers) and to perform a sample comparison with the Siemens ADVIA Centaur XP (Siemens Healthineers)., Methods: Within-day and between-day coefficient of variation (CV) were determined using serum sample pools and quality control materials. Six serum samples with decreasing concentrations of E2 were used to assess the limit of quantification. Linearity was evaluated using two different serum samples. Accuracy was evaluated by measuring three certified reference materials. Passing-Bablok regression and Bland-Altman plot were used for comparing Atellica and Centaur XP in 119 serum samples ranging from 45 to 10,059 pmol/L., Results: Within-day and between-day imprecision was <6.6%. Accuracy was <6.0% for all values except for 114 pmol/L (22%). The study of limit of quantification resulted in an interday imprecision <20%. High correlation between measured and expected estradiol dilution results was observed ( R  = 0.99), with recoveries ranging from 77 to 93%. Comparison study showed good agreement and no significant bias., Conclusions: The study shows that Atellica eE2 assay presents acceptable imprecision and accuracy and correlates well with Centaur XP., Competing Interests: Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication., (© 2020 Laura Macias-Muñoz et al., published by De Gruyter, Berlin/Boston.)

Introduction: Cushing syndrome (CS), an endogenous hypercortisolemic condition with increased cardiometabolic morbidity, leads to development of abdominal obesity, insulin resistance, diabetes and proatherogenic dyslipidemia. Zinc alpha-2 glycoprotein (ZAG) is a recently characterized lipolytic adipokine implicated in regulation of adipose tissue metabolism and fat distribution. In vitro and animal studies suggest that glucocorticoids interact with ZAG secretion and action. To assess the relationship between ZAG and glucocorticoids in a human model of hypercortisolism, circulating ZAG levels were tested in patients with CS and its counterpart controls., Methods: An observational, cross-sectional study on 39 women, 13 with active CS and 26 controls matched by age and body mass index. Plasma ZAG levels (μg/ml) were measured by ELISA and correlated with hypercortisolism, metabolic, and phenotypic parameters., Results: Plasma ZAG levels were significantly higher in patients with CS compared to controls (64.3±16.6 vs. 44.0±16.1, p=0.002). In a univariate analysis, ZAG levels positively correlated to 24-h urinary free cortisol (p=0.001), body mass index (p=0.02), non-esterified fatty acids (p=0.05), glucose (p=0.003), LDL-C (p=0.028), and type 2 diabetes mellitus (p=0.016), and were inversely related to total adiponectin levels (p=0.035). In a multivariate analysis, after adjusting for CS, ZAG levels only correlated with body mass index (p=0.012), type 2 diabetes mellitus (p=0.004), and glucose (p<0.001)., Conclusion: This study provides initial evidence that plasma ZAG levels are higher in patients with CS as compared to controls. The close relationship of ZAG with metabolic and phenotypic changes in CS suggests that ZAG may play a significant role in adipose tissue changes in hypercortisolism., (Copyright © 2017 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.)