Clinical Chemistry Podcast

Previously, carrier screening has been used in at-risk and specific ethnic populations, or for a limited number of diseases.  The broader screening approach, called expanded carrier screening, was endorsed in 2017 by the American College of Obstetricians and Gynecologists as an acceptable strategy for preconception and prenatal carrier screening.  This is expected to have a significant clinical impact, as targeted screening approaches likely have missed a large number of affected pregnancies due to the limited conditions tested, the unknown ethnic ancestry of many individuals, and the fact that the majority of children born with a genetic disease have no family history of the condition. When provided with results that their pregnancy is at-risk for a severe condition, study show approximately 80% of such couples pursue alternative reproductive options.  Given these consequences and the relative rarity of the included diseases, expanded carrier screening panels must have a high detection rate to correctly iden

Test standardization is a complex and multifaceted effort that’s remained a major goal for laboratory medicine’s professional societies, including the AACC and IFCC.  Hemoglobin A1c is an example of a test that has undergone global standardization due to its worldwide importance in diabetes screening, diagnosis, and care.  A key part of any standardization effort is aligning all manufacturers’ methods to an accepted reference method.  This was the main aim of the European Hemoglobin A1c trial devised by the IFCC’s Committee on Education and Use of Biomarkers in Diabetes. The August 2018 issue of Clinical Chemistry includes an original research article that describes the European Hemoglobin A1c trial and its results.

Proper handling during the collection and processing of specimens is crucial for producing reliable results.  These pre-analytical steps are highly vulnerable to the introduction of experimental bias and variance, which may drastically degrade specimen quality.  Analytes are affected differently by uncontrolled variations in specimen collection, processing, and storage protocols. The August 2018 issue of Clinical Chemistry includes a Review article from the Precision Medicine and Pharmacometabolomics Task Group of the Metabolomics Society.  The authors summarize the current variability among pre-analytical processing and biobanking procedures for metabolomics research and provide recommendations for best practices.

According to the World Health Organization, type 2 diabetes comprises the majority of the more than 400 million people with diabetes around the world. In efforts to better understand the disease, metabolomics measurements have identified tryptophan metabolites as potential biological mediators in the development of type 2 diabetes.  The PREDIMED trial was a multi-center trial of Mediterranean-style diets where the primary prevention of cardiovascular events that also included type 2 diabetes as a secondary end point. An original research article published in the August 2018 issue of Clinical Chemistry studies whether tryptophan metabolites in PREDIMED participants were associated with development of type 2 diabetes and insulin resistance.

It was once thought that RNA only existed within cells.  However, recent discoveries show that RNA is exported from cells and may be functional in cell to cell communication.  This extracellular RNA can be abundant and stable and is found in bodily fluids such as saliva.  Saliva has long been of interest for biomarker discovery and development, given its noninvasiveness and relative ease of collection. Despite these advantages, use of saliva for understanding more about extracellular RNA and its role in human biology and disease through RNA sequencing has some challenges.  The high bacterial content and low abundance of extracellular RNA in saliva mean that optimization of RNA library construction and isolation protocols are critical to the success of these RNA sequencing experiments. An original research article in the July 2018 issue of Clinical Chemistry compares different RNA isolation methods and library construction kits for long and small RNA sequencing of salivary extracellular RNA.  The authors descr

Liquid biopsy methods are an exciting area in cancer screening, diagnosis, and management.  These methods are aimed at measuring genomic signatures of tumor cells in the blood.  They rely on detection of circulating tumor cells, tumor-derived extracellular vesicles, or exosomes, or cell-free circulating DNA.  Liquid biopsy methods have been proposed to compliment, enhance or perhaps even replace tissue biopsy in some scenarios.  Liquid biopsy methods are an exciting area in cancer screening, diagnosis, and management.  These methods are aimed at measuring genomic signatures of tumor cells in the blood.  They rely on detection of circulating tumor cells, tumor-derived extracellular vesicles, or exosomes, or cell-free circulating DNA.  Liquid biopsy methods have been proposed to compliment, enhance or perhaps even replace tissue biopsy in some scenarios.   Beyond the minimal invasiveness, performing liquid biopsy may overcome some other weaknesses of tissue biopsy that are related to a single site’s inability

Laboratory testing is a key component of models of care for all types of lipid disorders.  New therapies demand accuracy of dyslipidemia testing at very low LDL cholesterol concentration ranges.  Inaccurate results lead to incorrect diagnosis and therapeutic management, both of which are costly to society and harmful to patients. To address these key issues of lipoprotein and apolipoprotein markers and reach consensus on contemporary lipid testing, a multidisciplinary panel was established by the European Federation of Clinical Chemistry and Laboratory Medicine and the European Atherosclerosis Society.       The July 2018 issue of Clinical Chemistry includes a special report from this joint consensus initiative.  It provides recommendations for improving the use of the lipid profile to assess cardiovascular disease risk conferred by atherogenic lipoproteins.