Clinical Chemistry Podcast

Hemoglobin A1c is widely used to monitor glycemic control and is now recommended for use in the diagnosis of diabetes. Although hemoglobin A1c has high reliability compared to the oral glucose tolerance test, there are certain settings in which such testing may be problematic and there is a growing interest in alternative markers of hyperglycemia.

Although hemoglobin A 1 C has high reliability , there a re certain settings in which hemoglobin A1C testing is thought to be problematic. 1 , 5 - anhydroglucitol or 1,5 - deoxyglucose is a monosaccharide originating mainly fr om foods and closely resembles glucose in structure , but is usually excreted by the kidneys.

Prenatal testing using blood specimens rather than more invasive sampling has been successfully used for common chromosome disorders and for clinically significant copy number variations . H owever , detecting single gene disorders which are caused by mutations remains an analytical challenge.

Human saliva has been increasingly used for biomarker development to allow noninvasive detection of diseases. Extracellular RNA was discovered in saliva about 10 years ago, and since then the nature, origin , and characterization of salivary RNA have been actively pursued.

In the last year, multiple clinical studies have shown the diagnosti c power of testing a patient's exome. Clinical exome testing is now available at over a dozen clinical laboratories in the US , and has been performed for thousands of patients.

Next generation sequencing (NGS)13 technology, also known as massively parallel sequencing (MPS), is being incorporated rapidly to clinical laboratory testing. Current applications include detection of germline variants in inherited diseases, somatic variants in cancers, subpopulations of circulating cell-free DNA, and single viral or microbial genomes in infections or metamicrobial genomes in normal or altered human flora. Each application is unique and has its advantages and disadvantages.

Extreme sports, extreme eating, extreme weight loss, extreme makeovers, just when you think you've heard it all, how about Extreme PCR?

Familial hypercholesterolemia is a genetic disorder characterized by increased plasma concentrations of low density lipoprotein cholesterol and premature symptoms of coronary heart disease. Early identification of at-risk individuals allows changes in lifestyle including dietary intervention and drug treatment. In the January 2015 issue of Clinical Chemistry, a Special Issue devoted to Molecular Diagnostics, a group of researchers in a multi-center study describes a genetic risk score procedure that distinguishes familial hypercholesterolemia patients from healthy subjects.

Extreme sports, extreme eating, extreme weight loss, extreme makeovers, just when you think you've heard it all, how about Extreme PCR?

For decades iron has been thought of as beneficial for the body. Most everyone knows that iron deficiency is harmful and that the condition should be treated by additional iron in the diet. However, too much iron can also be harmful to the body. Ferritin is a protein that stores iron and measurement of ferritin in serum is a measure of the iron deposits in the body.

Biobanking for clinical or research purposes includes the collection, processing, storage and analysis of biological specimens. It is now well-recognized that biobanking involves a complex array of technical, ethical, and regulatory considerations.

Kidney cancer is among the ten most frequently occurring cancers in the Western world and its incidence has been steadily rising each year. In the absence of symptoms, about 30% of patients with renalcell carcinomas are diagnosed with disease already in the metastatic stage.

Over the past decade genomic testing has emerged as a clinical tool available in multiple hospital and independent laboratories across the United States. In the November 2014 issue of Clinical Chemistry, an opinion article titled "Clinical Genomics: When Whole Genome Sequencing Is like a Whole-body CT Scan" framed the clinical utility of genomic testing in the context of another recently transformative test, whole-body computed tomography scanning, more commonly known as a CT scan.

In August 2014, the first patient with the Ebola virus disease arrived in the United States and was transported to Emory Hospital in Atlanta. While hospitals and laboratories knew that it was only a matter of time before this occurred, subsequent experience has shown that not all institutions in the U.S. were equally prepared for this eventuality. In this special podcast from Clinical Chemistry, we're joined by two members of the laboratory team that treated the first healthcare workers arriving from West Africa.

Using prohibited substances to enhance performance in sports, often referred to as doping, is a practice that's been with us all of recorded history. In ancient time, athletes or combatants were often supplied diets and supplements considered beneficial to enhance their performance.

Thrombosis and bleeding are among the foremost causes of morbidity and mortality, and the recent introduction of novel anticoagulants, anti-thrombotic, and hemostatic drugs has increased the need for rapid and accurate assessment of their activities. While the usual laboratory assessment of hemostasis, such as prothrombin time and other coagulation tests, are often effective, these methods may not identify all bleeding disorders.

Turnaround times are often long in PCR-based tests because multiple reactions are usually performed in parallel using programmable thermal cyclers. These methods typically use a single protocol, placing constraints on assay design.

Estimating Glomerular Filtration Rate or GFR is important for the detection and monitoring of impairment of renal function for safety in the use of potentially nephrotoxic pharmaceuticals and radiographic contrast media, and for administration of correct dosage of drugs cleared by the kidneys. Even though it is not ideal, serum creatinine is widely used as a marker for calculating Glomerular Filtration Rates.

Where are all the new omics-based tests? That's the question that Patrick Bossuyt asks in his paper appearing in the October 2014 issue of Clinical Chemistry. After billions of dollars worldwide have been spent upon omics-based research and announcements of many biomarker discoveries, clinical medicine has not gone through a radical change, despite all of the investment of time, money, and the collaboration of thousands of study participants.

Fragile X Syndrome is a severe neurodevelopmental disorder which is both complex and heterogeneous in both clinical phenotype and epigenotype. It is also one of the major inherited conditions co-morbid with autistic behaviors.

Fragile X Syndrome is a severe neurodevelopmental disorder which is both complex and heterogeneous in both clinical phenotype and epigenotype. It is also one of the major inherited conditions co-morbid with autistic behaviors.

In a 2009 study in Clinical Chemistry, Dr. Erna Lenters and Dr. Robbert Slingerland evaluated eight different points of care instruments measuring hemoglobin A1c and came to the conclusion that six of the eight did not meet generally accepted analytical performance criteria.

MicroRNAs measured in blood samples are promising, minimally invasive biomarker candidates that have recently been the target of many case control studies. However, the influence of age and gender is confounding variables and MicroRNAs remain largely unknown.

The cover of the September 2014 issue of Clinical Chemistry tells it all: one million downloads! That's the number of Clinical Chemistry podcasts that have been downloaded since the feature was initiated in 2009. It's a relatively new feature in the 60 years of publication of the journal, and the word podcast itself is only been in the vernacular for about 10 years.

Analysis of circulating RNA in the plasma of pregnant women can be a powerful tool for noninvasive prenatal testing and research. However, unbiased and high throughput detection of circulating RNA in plasma is a technical challenge.

Performing measurements that are comparable over time and location and across assays is essential for insuring appropriate clinical and public health practice. One step toward achieving this goal is using assays that are traceable to a higher-order reference measurement system or harmonized by using internationally recognized procedures.

Analysis of Human Chorionic Gonadotropin or hCG is usually associated with monitoring or detecting pregnancy. It is also a protein tumor marker for some cancers. In males, hCG stimulates testosterone production and has the potential to be abused by athletes in an attempt to enhance performance in sports.

There are few scientific papers that do not include the use of the P value to evaluate the statistical significance of results. However, use of this statistic may be misleading, as noted by a recent paper by Regina Nuzzo in the journal Nature. That paper served as a basis for commentary with additional examples by Drs. Jim Boyd and Tom Annesley in the July 2014 issue of Clinical Chemistry.

Chronic kidney disease is an important risk factor for cardiovascular morbidity and mortality. This risk is all the more important for patients undergoing hemodialysis. In the presence of clinical signs of an acute myocardial infarction, the universal definition includes the finding of a serum cardiac troponin concentration above the 99 percentile as defined by healthy individuals, together with time dependant changes in serum and troponin concentrations. But in contrast to individuals with normal kidney function the troponin concentrations in patients with chronic kidney disease, but no myocardial infarction, may already be at concentrations higher than the 99 percentile of a healthy population.

Central nervous system infections, including diseases like meningitis and encephalitis, are important public heath concerns across the globe, as they occur commonly and/or associated with high rates of mortality and morbidity. Measurement of biomarkers provide objective indicators of normal function or pathology, and can present information that may assist diagnosis, assessment of health condition, and evaluation of treatment safety and efficacy.

Early detection of acute myocardial infarction is crucial for deciding the course of treatment to preserve and prevent further damage to the myocardial tissue. During the last several years there has been a burgeoning interest in circulating microRNAs as potential novel biomarkers for acute myocardial infarction.

The universal definition of myocardial infarction requires both an increase in cardiac troponin concentrations and changes in values over serial measurements. However, exact criteria regarding the magnitude of change in troponin remain elusive. In the June 2014 issue of Clinical Chemistry, two studies on biological variation of serum troponins helped shed further light on the kinetics of this important cardiac marker.!

Laboratory test results are used to aid decisions in the diagnosis and treatment of disease. Consistent and comparable results from different measurement procedures are important for developing clinical practice guidelines, and for those guidelines to be applied to decisions about patient care. Yet results for many analytes are neither consistent nor comparable when measured using different clinical laboratory procedures.

One of the largest direct consumer genetic testing facilities, 23andMe, was ordered by the US Food and Drug Administration to cease marketing its Personal Genome Service test in late 2013. This occurred after 23andMe failed to respond to questions that the FDA had about the analytical and clinical validity of this test. While some support the FDA's actions because of the test potential for harm to consumers, some advocates of the technology fault the FDA for being overly paternalistic and impeding medical advances.

The clinical utility of molecular genetic testing relies on an accurate and comprehensive knowledge about the relationships between genes and variants, and diseases. Correctly interpreting the clinical significance of variants that may be detected continues to be a constant challenge for molecular diagnostic practice. This challenge has become substantially enlarged as next generation sequencing-based testing becomes rapidly integrated into routine clinical practice.

In the May issue of Clinical Chemistry, researchers involved in the Copenhagen City Heart Study found that lower nonfasting, circulating triglyceride concentrations are associated with lower all-cause mortality.

Increased nonfasting plasma triglycerides indicating increase amounts of cholesterol in remnant liver proteins and are important risk factors for cardiovascular disease. In the May issue of Clinical Chemistry, researchers involved in the Copenhagen City Heart Study found that lower circulating triglyceride concentrations are associated with lower all-cause mortality.

This is a podcast from Clinical Chemistry, sponsored by the Department of Laboratory Medicine at Boston Children's Hospital.

In well-resourced countries with a low incidence of tuberculosis, a major focus of TB control efforts is the detection and treatment of latent TB infection to prevent reactivation to active TB disease. This approach is particularly relevant for healthcare workers. Interferon Gamma Release Assays are used to detect the release of interferon from T cells stimulated by tuberculosis specific antigens. However, these tests differ in cost and complexity than the conventional tuberculin skin test.