Ferritin as a predictive biomarker of severity in Covid-19 / La ferritine comme biomarqueur prédictif des formes sévères de Covid-19

Background: To prevent the crisis-level shortage of beds in hospitals and for a more efficient support, it's necessary to early identify coronavirus disease-19 (Covid-19) patients at risk to develop a severe form of the disease. Objective: The goal of our study was to determine whether biological markers, including the serum ferritin, could predict the severity of the Covid-19. Methods: One hundred and seventy-one patients, who were admitted to Caen University Hospital, were included retrospectively with a positive diagnosis of Covid-19 by RT-PCR. A serum ferritin measurement was performed for all patients. They were further classified either into a non-severe or a severe group based on their hospitalization in intense care unit (ICU) for mechanical ventilation or death. Results: Univariate analysis revealed a significant association between increased serum ferritin and CRP levels, obesity, CT scan lesions, pathological respiratory rate, decreased PaO2/FiO2 ratio, the NEWS-2 score and the severe (n = 59) vs the non-severe (n = 112) outcome of Covid-19 patients. However, in a multivariate analysis, only CRP and obesity were associated with the severe form of Covid-19. Conclusion: While pathological level of serum ferritin at admission is associated with severe form of Covid-19, combination of increased CRP level and obesity would better predict the severity of the disease.

Pour une meilleure prise en charge, il est nécessaire de pouvoir identifier précocement les patients atteints de la Covid-19 susceptibles de développer une forme sévère. L'objectif de notre étude était de déterminer si des marqueurs biologiques, notamment la ferritinémie, peuvent prédire la sévérité de la Covid-19. Nous avons inclus de manière rétrospective 171 patients au CHU de Caen avec un diagnostic de Covid-19. Les patients devaient avoir un bilan biologique incluant la ferritinémie à l'admission et ont été classés en formes sévères (n = 59, hospitalisation et ventilation invasive en soins intensifs ou en réanimation, et/ou décès) et non-sévères (n = 112, tous les autres patients). L'analyse univariée a montré une association entre les formes sévères de Covid-19 avec les niveaux élevés de ferritine et de CRP, l'obésité, les lésions pulmonaires, la fréquence respiratoire élevée, la diminution du ratio PaO2/FiO2 et le score de NEWS-2. Cependant, en analyse multivariée seules la CRP et l'obésité montraient une association avec les formes sévères. En conclusion, alors que la ferritinémie élevée est associée à un risque accru de développer une forme sévère de la Covid-19, la CRP et la présence d'une obésité seraient de meilleurs marqueurs prédictifs.

Clinical reporting following the quantification of cerebrospinal fluid biomarkers in Alzheimer's disease: An international overview.

INTRODUCTION: The current practice of quantifying cerebrospinal fluid (CSF) biomarkers as an aid in the diagnosis of Alzheimer's disease (AD) varies from center to center. For a same biochemical profile, interpretation and reporting of results may differ, which can lead to misunderstandings and raises questions about the commutability of tests. METHODS: We obtained a description of (pre-)analytical protocols and sample reports from 40 centers worldwide. A consensus approach allowed us to propose harmonized comments corresponding to the different CSF biomarker profiles observed in patients. RESULTS: The (pre-)analytical procedures were similar between centers. There was considerable heterogeneity in cutoff definitions and report comments. We therefore identified and selected by consensus the most accurate and informative comments regarding the interpretation of CSF biomarkers in the context of AD diagnosis. DISCUSSION: This is the first time that harmonized reports are proposed across worldwide specialized laboratories involved in the biochemical diagnosis of AD.

[The detection of antithyroid antibodies in cerebrospinal fluid using fluorescent enzyme immuno assay (FEIA) is suitable for biological diagnosis of Hashimoto's encephalopathy]. / Détection des auto-anticorps antithyroïdiens dans le LCR par technique d'immunofluorométrie (FEIA) : application au diagnostic biologique de l'encéphalopathie d'Hashimoto.

Hashimoto encephalopathy (HE) is a rare condition often underdiagnosed. The clinical picture is heterogeneous with numerous neurological signs and is associated with the presence of high levels of anti-thyroperoxidase (TPO) and / or anti-thyroglobulin (TG) antibodies in the blood and cerebrospinal fluid (CSF). The determination of anti-TPO and anti-TG antibodies in CSF is performed in only few laboratories. The aim of our study was to adapt the EliATM fluoroenzymatic immuno assay (FEIA) to the detection of these autoantibodies in the CSF, and to compare the results with our previously published ELISA test (Blanchin S. 2007). For the FEIA technique, the detection threshold, and the quantification threshold have been determined for anti-TPO and anti-TG antibodies. FEIA results were concordant with ELISA at 75% and 100% for anti-TPO and anti-TG antibodies, respectively. Coefficients of variation (CV) of the intra-assay and inter-assay results were calculated as well as the uncertainties of measurement. The anti-TPO and anti-TG antibodies detection in CSF using FEIA technique correlate with the previously published ELISA and show good analytical performances. The availability of PhadiaTM 250 analyzer in a large number of laboratories will allow an easier biological detection. We hope that this test will respond to physician needs and help for HE diagnosis.

[Which are the significance of low level of glycated hemoglobin A1c?] / Hémoglobine glyquée A1c basse : quelles significations ?

Glycated hemoglobin A1c (HbA1c) reflects the mean blood glucose over the lifespan of red blood cells and has become a valuable tool both for diagnosis and monitoring of diabetes. Nevertheless, some factors may under-estimate the HbA1c value, compromising its application. The aim of this retrospective study was to evaluate the incidence rate of HbA1c lower than 4% and to identify some clinical and biological factors that can potentially reduce the HbA1c level. Between January 1st 2015 and October 1st 2017, we selected 17 patients with a HbA1c level lower than 4% that were measured in our laboratory of biochemistry at the university medical center of Caen. From the medical records, we identified medical conditions, treatments and biological parameters that could potentially explain a decrease of HbA1c level. Meanwhile the measurement of HbA1c, 8/16 patients had hemoglobin level lower than 100 g/L and 5/6 presented with reticulocytosis (>100 G/L). Ten patients over 17 suffered from hepatopathy (cirrhosis from various etiologies) with abnormal liver blood tests for 12 patients. Two patients showed hemolytic anemia and another one was investigated for hypoglycemia due to congenital hyperinsulinism. Finally, 3 patients were treated with drugs known to lower HbA1c levels. True hypoglycemia periods but also other circumstances which are known to alter erythrocytes lifespan or the glycation process may decrease HbA1c level. Such biological result should be critically interpreted and alternative biological markers should be considered.