Unexpected high levels of Cobalamin (Vitamin B12): Numerous interferences are decreased by PEG treatment.

Cobalamin (Vitamin B12) deficiency is a common cause of anemia. High levels of serum cobalamin is mainly due to cobalamin supplementation. It has also been associated with hematological malignancies, liver or renal diseases. Cobalamin is sometimes found elevated in autoimmune disorders and infectious diseases but concerns are raised on the fact that those serum increases might be due to interference with immunoassays. Those data’s shed the lights on the high prevalence of interference in patients with unexpected high cobalamin level. Precipitation with PEG appears to be an easy and costless method to increase the reliability of cobalamin dosage. In accordance with our results, we recommand to treat systematically every serum with a cobalamin >1500 ng/L

Neurofilament-light chains (NF-L), a biomarker of neuronal damage, is increased in sarcopenic patients: results of the sarcophage study

peer reviewe

Neurofilament light chain concentration in an aging population.

BACKGROUND: Neurofilament light chain (NF-L) concentration is recognized to be modified in neurological diseases and traumatic brain injuries, but studies in the normal aging population are lacking. It is, therefore, urgent to identify influencing factors of NF-L concentration in the aging population. METHOD: We assessed NF-L concentration in sera of a large cohort of 409 community-dwelling adults aged over 65 years. We studied the association between NF-L and various physiological factors but also with self-reported comorbidities or life-style habits. RESULTS: We showed that NF-L concentration in serum was tightly associated with cystatin C concentration (r = 0.501, p  5 points) in both univariate and multivariate analysis. Finally, we are providing reference ranges by age categories for subjects with or without altered renal function. CONCLUSION: NF-L concentration in the aging population is not driven by the increasing number of comorbidities or depression. Yet, NF-L blood concentration is dependent on kidney function and NF-L interpretation in patients suffering from renal failure should be taken with caution

Association of circulating hsa-miRNAs with sarcopenia: the SarcoPhAge study.

peer reviewed[en] OBJECTIVE: To identify a microRNA signature associated to sarcopenia in community-dwelling older adults form the SarcoPhAge cohort. METHODS: In a screening phase by next generation sequencing (NGS), we compared the hsa-miRome expression of 18 subjects with sarcopenia (79.6 ± 6.8 years, 9 men) and 19 healthy subjects without sarcopenia (77.1 ± 6 years, 9 men) at baseline. Thereafter, we have selected eight candidate hsa-miRNAs according to the NGS results and after a critical assessment of previous literature. In a validation phase and by real-time qPCR, we then analyzed the expression levels of these 8 hsa-miRNAs at baseline selecting 92 healthy subjects (74.2 ± 10 years) and 92 subjects with sarcopenia (75.3 ± 6.8 years). For both steps, the groups were matched for age and sex. RESULTS: In the validation phase, serum has-miRNA-133a-3p and has-miRNA-200a-3p were significantly decreased in the group with sarcopenia vs controls [RQ: relative quantification; median (interquartile range)]: -0.16 (-1.26/+0.90) vs +0.34 (-0.73/+1.33) (p < 0.01) and -0.26 (-1.07/+0.68) vs +0.27 (-0.55/+1.10) (p < 0.01) respectively. Has-miRNA-744-5p was decreased and has-miRNA-151a-3p was increased in the group with sarcopenia vs controls, but this barely reached significance: +0.16 (-1.34/+0.79) vs +0.44 (-0.31/+1.00) (p = 0.050) and  +0.35 (-0.22/+0.90) vs  +0.03 (-0.68/+0.75) (p = 0.054). CONCLUSION: In subjects with sarcopenia, serum hsa-miRNA-133a-3p and hsa-miRNA-200a-3p expression were downregulated, consistent with their potential targets inhibiting muscle cells proliferation and differentiation

Pediatric reference intervals: Retrospective study on thyroid horme levels

peer reviewedDefining reference range is an essential tool for diagnostic. Age and sexe influences on thyroid hormone levels have been already discussed. In this study, we are defining a new pediatric reference range for TSH, FT3 and FT4 for Cobas C6000 analyzer. To do so, we have taken in account 0 to 18 year old outclinic patients. During the first year of life, thyroid hormone levels change dramatically before getting stabilized around 3 years old. We also compared our results to those obtained in a Canadian large-scale prospective study (the CALIPER initiative)

Clinical chemistry laboratory assay of circulating oncology biomarkers : limitations and perspectives

peer reviewedIn 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