Clinical Chemistry Podcast

Cardiac troponins are recognized as the primary biomarkers used in the diagnosis of acute myocardial infarction.  These are commonly detected by immunoassays, which offer the wide availability and rapid results needed in clinical care scenarios to rule out myocardial infarction.  However, immunodetection methods can be limited when there is degradation of the target analyte, as is the case with cardiac troponin I. Early studies suggested that the central region, located between amino acid residues 30 and 110, was the most stable part of the molecule.  This was a driver for the majority of current diagnostic systems to utilize antibodies with epitopes located within the central region.  A down side to this approach is that auto antibodies also bind to this region, potentially causing interference and erroneous results. As more recent studies have identified additional cardiac troponin I proteolytic fragments, it is important to understand their composition and prevalence in the blood of patients with acute myo

The June 2018 issue of Clinical Chemistry published a Perspective article titled, “Clinical Utility of Transcriptome Sequencing: Towards a Better Diagnosis for Mendelian Disorders.”  In it, the authors Drs. Sumant Chakravorty and Madhuri Hegde discussed the impact of findings by Cummings and colleagues, who have shown for the first time in 2017 the clinical utility of next generation sequencing based transcriptome sequencing to increase molecular diagnostic yield by sequencing RNA.

Dementia is a devastating disease with a huge global impact. Today, over 46 million people live with dementia worldwide. It is possible that promising treatments for Alzheimer’s disease have failed thus far because treatment was started at a late stage of the disease process. So, early treatment could be beneficial, but how do you recognize a patient with Alzheimer’s disease if he or she does not present with clinical symptoms? This is a key question, and presents an enormous opportunity for laboratory test based on biological markers of ongoing brain pathology. One example is measurement of neurogranin, a protein in cerebrospinal fluid that correlates with cognitive decline and is a potential novel biomarker for Alzheimer’s disease dementia. There are multiple antibody-based neurogranin assays, which all target different segments of the protein. An original article in the June 2018 issue of Clinical Chemistry compared the analytical and the diagnostic performance of three commonly used neurogranin assays on

Tuberculosis is a prevalent and potentially deadly infectious disease with a worldwide incidence of more than 10 million new cases each year, and in 2015 alone, 1.4 million deaths were attributed to TB.  Much of the world relies on microbiologic techniques to detect tuberculosis including smear microscopy and mycobacterial culture which has a very long sample to answer timeframe. Both methods also have low clinical sensitivity for paucibacillary TB cases which account for more than 60% of new TB cases each year in emerging endemic areas such as China.  PCR-based methods are faster but also have limitations.  In the May 2018 issue of Clinical Chemistry, Dr. Tony Hu and his colleagues described a new peptide-based approach to detecting TB that overcomes those issues by using antibody conjugated nanoparticles, or nanodiscs, to bind specific peptides present in digested serum samples from cases of tuberculosis.  These are then detected by benchtop matrix-assisted laser desorption ionization-time-of-flight mass sp