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.

This is the September 2014 issue of Clinical Chemistry, Volume 60, Issue 9.

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.

Model of Human Hemoglobin. Imagine the days when

theses and dissertations were required to be written in Latin. In his 1825

Commentatio de vera materiae sanguini purpureum colorem impertientis natura,

Johann Friederich Engelhart proposed the molecular mass of hemoglobin to be an

astonishingly large 16000 Daltons per iron. No respectable scientist of the time

believed that molecules could be that large. We now know that hemoglobin has a

mass of ~64000 Daltons, is the major oxygen-carrying component of blood, and

can bind with glucose to form glycated hemoglobin (most commonly measured as

Hb A1c). Because Hb A1c is routinely measured for diagnosing diabetes and

prediabetes, as well as monitoring mean glycemia, it is important that Hb A1c

results be reliable. But how well do existing Hb A1c assays perform? This month's

issue of Clinical Chemistry contains the results from 2 studies of Hb A1c assay

performance, plus an accompanying editorial that discusses both of the studies.

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.