Optimisation of vitamin D status in global populations.

Vitamin D is important for musculoskeletal health. Concentrations of 25-hydroxyvitamin D, the most commonly measured metabolite, vary markedly around the world and are influenced by many factors including sun exposure, skin pigmentation, covering, season and supplement use. Whilst overt vitamin D deficiency with biochemical consequences presents an increased risk of severe sequelae such as rickets, osteomalacia or cardiomyopathy and usually warrants prompt replacement treatment, the role of vitamin D supplementation in the population presents a different set of considerations. Here the issue is to keep, on average, the population at a level whereby the risk of adverse health outcomes in the population is minimised. This position paper, which complements recently published work from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, addresses key considerations regarding vitamin D assessment and intervention from the population perspective. This position paper, on behalf of the International Osteoporosis Foundation Vitamin D Working Group, summarises the burden and possible amelioration of vitamin D deficiency in global populations. It addresses key issues including screening, supplementation and food fortification.

Intrinsic capacity and risk of death: Focus on the impact of using different diagnostic criteria for the nutritional domain.

OBJECTIVE: We aimed to estimate the ability of intrinsic capacity (IC) to predict death in community-dwelling older people using different diagnostic criteria to define the nutritional domain. METHODS: Participants from the Belgian SarcoPhAge cohort were followed from 2013 to the present. Four IC domains were assessed at baseline (data on the sensorial domain were not collected), and considered unsatisfactory below some specific thresholds. The nutritional domain was considered unsatisfactory if baseline malnutrition was present, defined by: 1) MNA-SF ≤11 points; 2) seven versions of the GLIM criteria, varying by the technique used to identify a reduced muscle mass; or 3) the combination of MNA-SF ≤11 points + GLIM criteria. The association between baseline unsatisfactory IC and 9-year mortality was calculated using the odds ratio (OR) adjusted for cofounders. RESULTS: Among the 534 participants (73.5 ± 6.2 years old; 60.3 % women at baseline), 157 (29.4 %) were dead after 9.3 ± 0.3 years of follow-up. Patients with baseline unsatisfactory IC in the locomotor domain (adjusted OR = 2.31 [95%CI 1.38-3.86]) or psychological domain (adjusted OR = 1.78 [1.12-2.83]) were at higher mortality risk. Regarding malnutrition, unsatisfactory IC in the nutrition domain was strongly associated with a higher mortality risk, whatever the criteria used to identify a reduced muscle mass. The highest association with mortality was found in participants with a baseline unsatisfactory nutritional domain defined by the combination of MNA-SF + GLIM criteria (adjusted OR = 3.27 [95%CI 1.72-6.23]). CONCLUSIONS: Presenting any unsatisfactory IC at baseline was associated with a higher 9-year mortality risk in community-dwelling older people. The sequential incorporation of MNA-SF and GLIM criteria as the IC nutritional domain would be helpful to guide public health actions towards healthy ageing.

[Biological markers of inflammation : an update]. / Les marqueurs biologiques de l'inflammation : faisons le point.

Biomarkers of inflammation such as sedimentation rate, C-reactive protein and procalcitonin are used in daily clinical practice for the diagnosis, prognosis and follow-up of patients with fever or inflammatory syndrome. The purpose of this article is to summarize the current knowledge about these main biological tests and to discuss new biomarkers and new assay approaches such as multiplex technology.

: Le dosage des biomarqueurs de l'inflammation, tels que la vitesse de sédimentation, la protéine-C réactive et la procalcitonine, est utilisé quotidiennement dans le cadre du diagnostic, du pronostic et du suivi des patients fébriles ou souffrant de syndrome inflammatoire. Le but de cet article est de résumer les connaissances actuelles quant à ces principaux tests biologiques et d'aborder les nouveaux biomarqueurs ainsi que les nouvelles approches de dosage comme la technologie multiplex.

[Diagnostic approach to chronic kidney disease]. / Vignette diagnostique de l'étudiant. Approche diagnostique de la maladie rénale chronique.

Chronic kidney disease (CKD) affects ~7 % of the general population and is burdened with significant morbidity and mortality, especially cardiovascular disease. At the terminal stage, CKD requires demanding and costly treatments for the patient and the society, such as dialysis or kidney transplantation. The symptomatology of CKD is poor and unspecific, which complicates the identification and early management of patients with CKD. Diagnostic criteria for CKD include (1) renal morphological abnormality; and/or (2) proteinuria superior to150 mg/g creatinine; and/or (3) glomerular filtration rate (GFR) inferior to 60 ml/min/ 1.73 m². The persistence of these abnormalities for more than 3 months indicates the chronicity of the renal damage. Starting from an exemplary clinical case, we detail the diagnostic steps when faced with a suspicion of CKD.

: La maladie rénale chronique (MRC) touche ~7 % de la population générale et est grevée d'une morbi-mortalité, notamment cardiovasculaire, significative. à son stade terminal, la MRC nécessite des traitements lourds et coûteux pour le patient et pour la société, tels que la dialyse ou la transplantation rénale. La symptomatologie de la MRC est frustre et aspécifique, ce qui complique l'identification et la prise en charge précoce des patients insuffisants rénaux chroniques. Les critères diagnostiques de la MRC incluent (1) une anomalie morphologique rénale, et/ou (2) une protéinurie sup�rieur a 150 mg/g créatininurie, et/ou (3) un débit de filtration glomérulaire (DFG) inf�rieur a 60 ml/min/1,73 m². La persistance de ces anomalies pendant plus de 3 mois signe la chronicité de l'atteinte rénale. Au départ d'une vignette clinique paradigmatique, nous détaillons les étapes diagnostiques face à une suspicion de MRC.

American Bison (Bison bison) reproductive endocrinology: serum Pregnancy Associated Glycoproteins (PAG), Progesterone, Estrone and Estrone-Sulfate in non pregnant animals and during gestation.

This study describes concentrations of Pregnancy Associated Glycoproteins (PAG), progesterone (P4), estrone (E1) and estrone-sulfate (E1S) in American Bison sera. In 2 ranches, mature American Bison were sampled once a year for 2 yr. Subsequent American Bison cows calving days were reported. PAG concentration was determined by Radio-Immuno Assay, whereas P4, E1 and E1S were assayed using Liquid Chromatography and Mass Spectrometry. Concentrations were compared between American Bison bulls (B, n = 7), Nonpregnant cows (NP, n = 32), first (1TP, n = 3), second (2TP, n = 26) and third (3TP, n = 15) trimester of pregnancy. Seven American Bison bulls and 92 cows were sampled, 51 calved during these 2 yr. Calving occurred mostly in spring (74.5%), but also in summer (13.7%) and fall (11.8%). PAG and P4 were higher in 2TP and 3TP than B and NP (P< 0.0001). P4 was non-basal in B and NP. E1 and E1S were correlated (P< 0.0001; r = 0.76) and increased in 2TP and 3TP when compared with B and NP (P< 0.01). Moreover, E1S was higher in 3TP than in 2TP (P< 0.0001) and correlated to pregnancy day (P< 0.0001; r = 0.60). Breeding American Bison in Belgium induces a calving seasonality loss. P4 slowly increases in 1TP and remains steady and high in 2 and 3TP. P4 non-basal and variable concentrations in B or NP disable its use as gestation marker. American Bison produce PAG in the 2 and 3TP, but Estrone-sulfate assay seems to be the best pregnancy marker during the 2 last trimesters as it could help to estimate the gestation period.

[Clinical chemistry laboratory assay of circulating oncology biomarkers : limitations and perspectives]. / Dosage au laboratoire de chimie clinique des biomarqueurs circulants oncologiques : limites et perspectives.

In current practice, the use of circulating oncological biomarkers by clinicians is almost inseparable from cancer patients management. However, the interpretation of the results is not always easy because it is more specific to laboratory medicine and involves notions of peri-analytical orders as well as analytical sensitivity and specificity. In the past, the development of new analytical techniques improved the analytical sensitivity or allowed the implementation of new biomarkers; this observation would still be true today. Mass spectrometry, microRNA assay, or Single Molecule Array (SiMoA) are recent analytical developments with very good analytical performances that could contribute to the improvement of cancer patient management.

Dans la pratique courante, le recours des cliniciens aux biomarqueurs circulants oncologiques est presque indissociable de la prise en charge des patients cancéreux. Cependant, l'interprétation des résultats n'est pas toujours aisée. Elle est, en effet, plus spécifique à la médecine de laboratoire faisant intervenir des notions d'ordres péri-analytiques ainsi que celles de sensibilité et spécificité analytiques. Comme il a été démontré par le passé, le développement de nouvelles techniques d'analyses a permis d'abaisser le seuil de sensibilité analytique, ou encore, l'implémentation de nouveaux biomarqueurs; cette observation se vérifierait encore aujourd'hui. La spectrométrie de masse, le dosage des microARN, ou encore le Single Molecule Array (SiMoA) sont des méthodes d'analyse récentes présentant de très bonnes performances analytiques qui pourraient contribuer à l'amélioration de la prise en charge des patients cancéreux.

How can the orthopedic surgeon ensure optimal vitamin D status in patients operated for an osteoporotic fracture?

In this narrative review, the role of vitamin D deficiency in the pathophysiology, healing of fragility fractures, and rehabilitation is discussed. Vitamin D status can be assessed by measuring serum 25(OH)-vitamin D level with standardized assays. There is a high prevalence of vitamin D insufficiency (25(OH)D < 50 nmol/l (i.e., 20 ng/mL)) or deficiency (25(OH)D < 25 nmol/l (i.e., 10 ng/mL)) in patients with fragility fractures and especially in those with a hip fracture. The evidence on the effects of vitamin D deficiency and/or vitamin D supplementation on fracture healing and material osseointegration is still limited. However, it appears that vitamin D have a rather positive influence on these processes. The fracture liaison service (FLS) model can help to inform orthopedic surgeons, all caregivers, and fractured patients about the importance of optimal vitamin D status in the management of patients with fragility fractures. Therefore, vitamin D status should be included in Capture the Fracture® program as an outcome of FLS in addition to dual-energy X-ray absorptiometry (DXA) and specific antiosteoporosis medication. Vitamin D plays a significant role in the pathophysiology and healing of fragility fractures and in rehabilitation after fracture. Correction of vitamin D deficiency should be one of the main outcomes in fracture liaison services.

A Multicenter Study to Evaluate Harmonization of Assays for C-Terminal Telopeptides of Type I Collagen (ß-CTX): A Report from the IFCC-IOF Committee for Bone Metabolism (C-BM).

BACKGROUND: Biochemical bone turnover markers are useful tools to assess bone remodeling. C-terminal telopeptide of type I collagen (ß-CTX) has been recommended as a reference marker for bone resorption in research studies. METHODS: We describe the results of a multicenter study for routine clinical laboratory assays for ß-CTX in serum and plasma. Four centers (Athens GR, Copenhagen DK, Liege BE and Sheffield UK) collected serum and plasma (EDTA) samples from 796 patients presenting to osteoporosis clinics. Specimens were analyzed in duplicate with each of the available routine clinical laboratory methods according to the manufacturers' instructions. Passing-Bablok regressions, Bland-Altman plots, V-shape evaluation method, and Concordance correlation coefficient for ß-CTX values between serum and plasma specimens and between methods were used to determine the agreement between results. A generalized linear model was employed to identify possible variables that affected the relationship between the methods. Two pools of serum were finally prepared and sent to the four centers to be measured in 5-plicates on 5 consecutive days with the different methods. RESULTS: We identified significant variations between methods and between centers although comparison results were generally more consistent in plasma compared to serum. We developed univariate linear regression equations to predict Roche Elecsys®, IDS-iSYS, or IDS ELISA ß-CTX results from any other assay and a multivariable model including the site of analysis, the age, and weight of the patient. The coefficients of determination (R2) increased from approximately 0.80 in the univariate model to approximately 0.90 in the multivariable one, with the site of analysis being the major contributing factor. Results observed on the pools also suggest that long-term storage could explain the difference observed with the different methods on serum. CONCLUSION: Our results show large within- and between-assay variation for ß-CTX measurement, particularly in serum. Stability of the analyte could be one of the explanations. More studies should be undertaken to overcome this problem. Until harmonization is achieved, we recommend measuring ß-CTX by the same assay on EDTA plasma, especially for research purposes in large pharmacological trials where samples can be stored for long periods before they are assayed.

[Retrospective study of the thyroid balance in pregnant women : definition of TSH and FT4 reference values]. / Étude rétrospective du bilan thyroïdien chez les femmes enceintes : définition des valeurs de référence de TSH et FT4.

Pregnancy leads to many physiological changes, particularly in the thyroid. This implies that the reference values of the thyroid parameters may change according to the trimesters of the pregnancy and that the management of pregnant women differs. Establishing reference values is not easy and can be done in several ways. In our study, we review the reference values of TSH and FT4 of pregnant women followed up at Liege University Hospital compared to control women. This has been achieved using retrospective data from our laboratory. We show that the small decrease in the TSH reference values in pregnant women is barely visible in a small cohort. Our FT4 values confirm what the literature shows, i.e. a slight increase during the first trimester. We emphasize the difficulty and the relevance of making reference values for pregnant women.

La grossesse aboutit à de nombreux changements physiologiques, en particulier vis-à-vis de la fonction thyroïdienne. Ceci implique que les valeurs de référence du bilan thyroïdien changent en fonction des trimestres et que la prise en charge des femmes enceintes diffère. Établir des valeurs de référence n'est pas un travail aisé et peut être fait de plusieurs façons. Dans notre étude réalisée au CHU de Liège, nous revoyons les valeurs de référence de TSH et FT4 de femmes enceintes par rapport à des femmes contrôles. Ceci a été réalisé à partir de données rétrospectives de notre laboratoire. Nous montrons que la faible diminution des valeurs de référence de la TSH chez la femme enceinte est peu visible sur une petite cohorte. Nos valeurs de FT4 confirment ce que montre la littérature, à savoir une légère augmentation durant le premier trimestre. Nous soulignons la difficulté et la pertinence de définir des valeurs de référence chez la femme enceinte.

The impact of an ultra-trail on the dynamic of cardiac, inflammatory, renal and oxidative stress biological markers correlated with electrocardiogram and echocardiogram.

The aim of this study was to describe the effects of a 64.2 km ultra-trail on the biomarkers of muscle damage, inflammation and oxidative stress, and compare the results observed with an ECG and an echocardiogram, both performed before and after the race.Thirty-three ultra-trail volunteers (45.8 ± 8.7 years old) were enrolled in our study. Three blood tests were drawn from each runner, one just before (TPRE), one just after (TPOST) and the last 3 h after the end of the race (TPOST3h).All the markers increased. The maximum concentrations observed were at TPOST3h and were significant (p < 0.001) for creatine kinase, creatine kinase isoform MB, high-sensitivity C-reactive protein, uric acid and for the ratio of reduced glutathione to oxidised glutathione. However, in the case of myoglobin, high-sensitive troponin T, N-terminal pro-brain natriuretic peptide, oxidised glutathione, myeloperoxidase, cystatin C and creatinine, the most significant increases were at TPOST (p < 0.001). Modifications were observed in the medical imaging using echocardiography such as reduction of left ventricule end-sytolic and diastolic volumes and left ventricular global longitudinal strain. ECG showed electrical criteria for left ventricular hypertrophy and incomplete right bundle branch block after the race.Endurance races cause significant physiological stress to the body that can be measured by the increase of different biomarkers. From a laboratory perspective, it is important to take into account the possible exercise performed previous to the testing to avoid a misinterpretation of the results. From a training perspective, due to these increases in biomarkers, it is recommended that runners wait at least 72 h after an ultra-trail before subsequent training. In addition a transient impairment of ventricular function due to dehydration were observed.

Could KL-6 levels in COVID-19 help to predict lung disease?

BACKGROUND: Coronavirus disease COVID-19 has become a public health emergency of international concern. Together with the quest for an effective treatment, the question of the post-infectious evolution of affected patients in healing process remains uncertain. Krebs von den Lungen 6 (KL-6) is a high molecular weight mucin-like glycoprotein produced by type II pneumocytes and bronchial epithelial cells. Its production is raised during epithelial lesions and cellular regeneration. In COVID-19 infection, KL-6 serum levels could therefore be of interest for diagnosis, prognosis and therapeutic response evaluation. MATERIALS AND METHODS: Our study retrospectively compared KL-6 levels between a cohort of 83 COVID-19 infected patients and two other groups: healthy subjects (n = 70) on one hand, and a heterogenous group of patients suffering from interstitial lung diseases (n = 31; composed of 16 IPF, 4 sarcoidosis, 11 others) on the other hand. Demographical, clinical and laboratory indexes were collected. Our study aims to compare KL-6 levels between a COVID-19 population and healthy subjects or patients suffering from interstitial lung diseases (ILDs). Ultimately, we ought to determine whether KL-6 could be a marker of disease severity and bad prognosis. RESULTS: Our results showed that serum KL-6 levels in COVID-19 patients were increased compared to healthy subjects, but to a lesser extent than in patients suffering from ILD. Increased levels of KL-6 in COVID-19 patients were associated with a more severe lung disease. DISCUSSION AND CONCLUSION: Our results suggest that KL-6 could be a good biomarker to assess ILD severity in COVID-19 infection. Concerning the therapeutic response prediction, more studies are necessary.

The Belgian Bone Club 2020 guidelines for the management of osteoporosis in postmenopausal women.

PURPOSE: To provide updated evidence-based guidelines for the management of osteoporosis in postmenopausal women in Belgium. METHODS: The Belgian Bone Club (BBC) gathered a guideline developer group. Nine "Population, Intervention, Comparator, Outcome" (PICO) questions covering screening, diagnosis, non-pharmacological and pharmacological treatments, and monitoring were formulated. A systematic search of MEDLINE, the Cochrane Database of Systematic Reviews, and Scopus was performed to find network meta-analyses, meta-analyses, systematic reviews, guidelines, and recommendations from scientific societies published in the last 10 years. Manual searches were also performed. Summaries of evidence were provided, and recommendations were further validated by the BBC board members and other national scientific societies' experts. RESULTS: Of the 3840 references in the search, 333 full texts were assessed for eligibility, and 129 met the inclusion criteria. Osteoporosis screening using clinical risk factors should be considered. Patients with a recent (<2 years) major osteoporotic fracture were considered at very high and imminent risk of future fracture. The combination of bone mineral density measured by dual-energy X-ray absorptiometry and 10-year fracture risk was used to categorize patients as low or high risk. Patient education, the combination of weight-bearing and resistance training, and optimal calcium intake and vitamin D status were recommended. Antiresorptive and anabolic osteoporosis treatment should be considered for patients at high and very high fracture risk, respectively. Follow-up should focus on compliance, and patient-tailored monitoring should be considered. CONCLUSION: BBC guidelines and 25 guideline recommendations bridge the gap between research and clinical practice for the screening, diagnosis, and management of osteoporosis.

How to manage osteoporosis before the age of 50.

This narrative review discusses several aspects of the management of osteoporosis in patients under 50 years of age. Peak bone mass is genetically determined but can also be affected by lifestyle factors. Puberty constitutes a vulnerable period. Idiopathic osteoporosis is a rare, heterogeneous condition in young adults due in part to decreased osteoblast function and deficient bone acquisition. There are no evidence-based treatment recommendations. Drugs use can be proposed to elderly patients at very high risk. Diagnosis and management of osteoporosis in the young can be challenging, in particular in the absence of a manifest secondary cause. Young adults with low bone mineral density (BMD) do not necessarily have osteoporosis and it is important to avoid unnecessary treatment. A determination of BMD is recommended for premenopausal women who have had a fragility fracture or who have secondary causes of osteoporosis: secondary causes of excessive bone loss need to be excluded and treatment should be targeted. Adequate calcium, vitamin D, and a healthy lifestyle should be recommended. In the absence of fractures, conservative management is generally sufficient, but in rare cases, such as chemotherapy-induced osteoporosis, antiresorptive medication can be used. Osteoporosis in young men is most often of secondary origin and hypogonadism is a major cause; testosterone replacement therapy will improve BMD in these patients. Diabetes is characterized by major alterations in bone quality, implying that medical therapy should be started sooner than for other causes of osteoporosis. Primary hyperparathyroidism, hyperthyroidism, Cushing's syndrome and growth hormone deficiency or excess affect cortical bone more often than trabecular bone.

[Tandem-mess spectrometry coupled with liquid chromatography (LCMS/MS) : a revolution in the clinical chemistry laboratory]. / La chromatographie liquide couplée à un spectromètre de masse en tandem (LC-MS/MS) : une révolution dans le laboratoire de chimie clinique.

Manual or automated immunoassays are largely used in clinical chemistry laboratories for measuring various compounds like steroid or peptide hormones. However, these methods can lack sensibility and specificity. Hence, during this last decade, tandem-mess spectrometry coupled with liquid chromatography (LC-MS/MS) have emerged as a technique of choice to precisely quantify those molecules. However, these instruments remain quite expensive and need highly trained people.

Les laboratoires de biologie clinique réalisent, depuis de très nombreuses années, des dosages de différentes molécules (hormones, peptides, stéroïdes,…) grâce à des méthodes analytiques utilisant des anticorps. Ces méthodes, faciles à utiliser sont, pour la plupart d'entre elles, totalement automatisables. Cependant, ces méthodes dites «immunologiques¼ manquent parfois de sensibilité et surtout de spécificité. Durant cette dernière décennie, la spectrométrie de masse en tandem couplée à la chromatographie liquide (LC-MS/MS) s'est de plus en plus imposée dans les laboratoires de chimie clinique comme une alternative aux immunodosages. En effet, cette technique permet de séparer et de quantifier avec précision des molécules dont la structure est proche et qui ne sont pas bien différenciées avec des immunodosages. Aussi, la sensibilité de la LC-MS/MS peut être également supérieure à celle des immunodosages. Par contre, ce type de technologie demande du matériel de pointe assez coûteux et un personnel hautement qualifié.

European Biological Variation Study (EuBIVAS): within- and between-subject biological variation estimates of ß-isomerized C-terminal telopeptide of type I collagen (ß-CTX), N-terminal propeptide of type I collagen (PINP), osteocalcin, intact fibroblast growth factor 23 and uncarboxylated-unphosphorylated matrix-Gla protein-a cooperation between the EFLM Working Group on Biological Variation and the International Osteoporosis Foundation-International Federation of Clinical Chemistry Committee on Bone Metabolism.

We have calculated the biological variation (BV) of different bone metabolism biomarkers on a large, well-described cohort of subjects. BV is important to calculate reference change value (or least significant change) which allows evaluating if the difference observed between two consecutive measurements in a patient is biologically significant or not. INTRODUCTION: Within-subject (CVI) and between-subject (CVG) biological variation (BV) estimates are essential in determining both analytical performance specifications (APS) and reference change values (RCV). Previously published estimates of BV for bone metabolism biomarkers are generally not compliant with the most up-to-date quality criteria for BV studies. We calculated the BV and RCV for different bone metabolism markers, namely ß-isomerized C-terminal telopeptide of type I collagen (ß-CTX), N-terminal propeptide of type I collagen (PINP), osteocalcin (OC), intact fibroblast growth factor 23 (iFGF-23), and uncarboxylated-unphosphorylated Matrix-Gla Protein (uCuP-MGP) using samples from the European Biological Variation Study (EuBIVAS). METHODS: In the EuBIVAS, 91 subjects were recruited from six European laboratories. Fasting blood samples were obtained weekly for ten consecutive weeks. The samples were run in duplicate on IDS iSYS or DiaSorin Liaison instruments. The results were subjected to outlier and variance homogeneity analysis before CV-ANOVA was used to obtain the BV estimates. RESULTS: We found no effect of gender upon the CVI estimates. The following CVI estimates with 95% confidence intervals (95% CI) were obtained: ß-CTX 15.1% (14.4-16.0%), PINP 8.8% (8.4-9.3%), OC 8.9% (8.5-9.4%), iFGF23 13.9% (13.2-14.7%), and uCuP-MGP 6.9% (6.1-7.3%). CONCLUSIONS: The EuBIVAS has provided updated BV estimates for bone markers, including iFGF23, which have not been previously published, facilitating the improved follow-up of patients being treated for metabolic bone disease.

Biotin supplementation causes erroneous elevations of results in some commercial serum 25-hydroxyvitamin d (25OHD) assays.

The Vitamin D External Quality Assessment Scheme (DEQAS) distributes serum samples globally, on a quarterly basis, to assess participants' performance of specific methods for 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D). DEQAS occasionally circulates samples containing high levels of substances found in certain clinical situations e.g. 25-OHD2, 24,25-(OH)2D3, hypertriglyceridemia. The increased availability and use of health supplements containing biotin has led to case reports of assay interference in methods utilizing a biotin-streptavidin detection system. In October 2018, DEQAS included a serum sample (545) containing exogenous biotin (concentration =586 µg/L) which was analyzed by a total of 683 laboratories using 35 different methods. The same serum sample (544) without exogenous biotin was also included in the 5-sample set. All methods (760 laboratories) performed satisfactorily on sample 544 giving an All-Laboratory Trimmed Mean = 50.2 ± 6.5 nmol/L (±SD, CV = 12.9 %). The target value for this sample 544 (& 555) was 47.4 nmol/L as determined by Centers for Disease Control and Prevention (CDC) Atlanta, Georgia using their LC-MS/MS reference method. In contrast, #545 containing the exogenous biotin was reported by only 683 laboratories and gave an All-Laboratory Trimmed Mean = 66.8 ± 37.6 nmol/L (±SD, CV = 56.3 %). As expected, LC-MS/MS methods (143 labs) reported similar results for both 544 = 48.9 ± 4.4 nmol/L (±SD) and 545 = 48.3 ± 4.5 nmol/L (±SD) showing that assays involving chromatographic steps are unaffected by the presence of biotin. Several of the antibody-based assays including Abbott Architect, DiaSorin Liaison, Beckman Unicel and Siemens Centaur are also unaffected by the addition of biotin. Two assays, IDS-iSYS and Roche Total 25OHD, both of which use biotin-streptavidin, exhibit biotin interference yielding values with a significant positive bias for 545 of 102.6 nmol/L ± 78.7 nmol/L (±SD) and 517.8 nmol/L ± 209.8 nmol/L (±SD) respectively. Interestingly, the failure to report sample 545 data from 77 laboratories is due solely to those running Roche Total 25OHD or Roche Vitamin D Total II assays. Given the prevalence of the adversely affected assays (25 % of DEQAS users) and the high volume of 25OHD testing, clinicians using these assays should, where possible, only measure 25OHD when patients are off biotin.

Intense sport practices and cardiac biomarkers.

Biomarkers are well established for the diagnosis of myocardial infarction, heart failure and cardiac fibrosis. Different papers on cardiac biomarker evolution during exercise have been published in the literature and generally show mild to moderate elevations. However, the mechanism responsible for these elevations, reflecting physiological or even pathophysiological changes, still has to be clearly elucidated. There are also indications of higher cardiac risk in poorly trained athletes than in well-trained athletes. Whether regular repetition of intensive exercise might lead, in the longer term, to fibrosis and heart failure remains to be determined. In this review, we summarized the main research about the effects of intense exercise (in particular, running) on cardiac biomarkers (including troponins, natriuretic peptides, etc.). We found that cardiac fibrosis biomarkers seemed to be the most informative regarding the biological impact of intense physical activity.

Harmonization of commercial assays for PINP; the way forward.

International Federation of Clinical Chemistry and Laboratory Medicine and The International Osteoporosis Foundation Joint Committee on Bone Metabolism believes that the harmonization of PINP assays is an achievable and practical goal. INTRODUCTION: In order to examine the agreement between current commercial assays, a multi-center study was performed for PINP in serum and plasma. METHODS: The automated methods for PINP (Roche Cobas and IDS iSYS) gave similar results. A significant proportional bias was observed between the two automated assays and the Orion radioimmunoassay (RIA) for PINP. RESULTS: Results from other published studies comparing PINP values among these three assays broadly support our findings. Taken together, these results confirm that harmonized PINP measurements exist between the two automated assays (Roche Cobas and IDS iSYS) when the eGFR is > 30 mL/min/1.73m2, but a significant bias exists between the Orion RIA and the two automated assays. CONCLUSION: Therefore, in subjects with normal renal function, PINP results reported by the Roche Cobas and IDS iSYS assays are similar and may be used interchangeably, and similar reference intervals and treatment targets could be applied for the two automated assays. Harmonization between the automated assays and the RIA is potentially possible with the use of common calibrators and the development of a reference method for PINP. This should also help ensure that any new commercial assay developed in the future will attain similar results. IOF and IFCC are committed to working together towards this goal with the cooperation of the reagent manufacturing industry.

Detection of wheat allergens using 2D Western blot and mass spectrometry.

BACKGROUND: Wheat allergy is relatively common and the associated clinical manifestations depend on the involved molecular allergens as well as on the way of exposure. Different symptoms have been described: wheat-dependent exercise-induced anaphylaxis (WDEIA), atopic dermatitis (AD) and pollen rhinitis (PR). Traditional diagnostic methods do not allow accurate molecular identification of the allergens that are essential for risk assessment and for the choice of the most adapted treatment. METHODS: Standardized total protein extracts obtained from wheat seeds were separated by 2D electrophoresis. Twenty-one sera with high wheat-specific immunoglobulin E (sIgE) levels were classified into three patients groups based on their clinical profile. These sera were tested by Western blot on 2D separated standardized wheat protein extract and their sIgE sensitization profiles were compared. RESULTS: Specific sensitization profiles were identified for each phenotype group. For WDEIA, protein spots around 37 kDa (pH 6-9) and 37-50 kDa (pH 5-6) were identified. For AD, spots were observed around 50 kDa (pH 9), 10 kDa (pH 9) and 20 to 75 kDa (pH3). For PR, specific spots were located around 90 kDa (pH 9). The mass spectrometry (UHPLC-MS/MS) analysis of these identified spots pointed out several potential interesting allergens: Tri a 26, Tri a bA, Tri a 34, Tri a tritin. CONCLUSIONS: The present study allowed the identification of different protein areas specific to these studied groups. The protein spots of interest were identified by UHPLC-MS/MS. It has been possible to establish a link between a specific symptomatology and the newly identified responsible allergens.