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Hemoglobin A1C is one of the analytes most commonly measured in clinical laboratories in patients with diabetes mellitus. Physicians use Hemoglobin A1C to monitor long-term glycemic control, adjust therapy, and predict complications of diabetes. It was recently added as a criterion for diagnosis of diabetes.

Although standardization of barcodes and label formats has lowered the number of mislabeled specimens in clinical laboratories, it remains a potential source of pre-analytical error. Published error rates of mislabeled specimens range up to as high as just over 1 percent.

On the cover this month: Activated platelets. These irregularly shaped blood components are vital for the normal clotting process. However, platelets also play a role in blood clot formation on arterial stents or on ruptured atherosclerotic plaques, leading to blockage of blood flow and tissue ischemia. For some patients, antiplatelet agents must be used to prevent arterial thrombosis. During therapy, platelet function tests are used to monitor response. Newer approaches to monitoring coagulation, such as viscoelastic coagulation testing, are being introduced. Controversy exists surrounding the tests for monitoring response to antiplatelet therapy or for guiding transfusion decisions in critically ill patients. This issue of Clinical Chemistry contains a Q&A in which 4 experts discuss how they define aspirin and clopidogrel response, what platelet function tests are used at their institutions, the role of the laboratory in guiding antiplatelet therapy, and what tests they believe have the greatest potential t

Gestational diabetes mellitus is often defined as any degree of glucose intolerance during pregnancy. Fetal complications and adverse outcomes for both the fetus and the mother are important concerns in gestational diabetes.

Acute kidney injury is an important health problem. Patients who develop acute kidney injury have increased in-hospital mortality, and if they do survive, they still suffer long-term increased morbidity and mortality. For that reason there has been great interest in the development of biomarkers that could identify kidney injury in its earliest stages, at a time when interventions might be more successful.

In March of 2013, the ACMG, The American College of Medical Genetics and Genomics, issued a clinical laboratory guideline for the reporting of incidental findings observed through exome and genome sequencing, including the ethical implications of reporting these incidental findings.

The discovery phase of proteomics is essential for the identification of suitable markers for exploration and validation of promising new clinical tests. But can researchers be certain if what they believe they are measuring is in fact what they are actually measuring?

This is the February 2014 issue of Clinical Chemistry, Volume 60, Issue 2.

Until recently, much of the research in medical literature used primarily male populations. Slowly we've come to appreciate the importance of studying female populations due to the differences in normal physiology as well as disease pathology between men and women.

Women who present with acute coronary events are less frequently to be properly diagnosed and often have worse outcomes than men. Part of the problem may be that women are less apt to manifest increased biomarkers or often receive less aggressive guideline-mandated care. Women also have lower reference values for biomarkers of cardiac injury that are rarely taken into account.

The development of in vitro fertilization in the 1970s has revolutionized the treatment of infertility. The ability to culture embryos has allowed for the development of the preimplantation genetic diagnosis. This involves removing a cell from the developing embryos for genetic testing before choosing one to implant. Just like prenatal diagnosis, it is used to screen for various genetic diseases before birth. For women of advanced maternal age or couples with known genetic mutations, the ability to screen of embryos free of certain genetic mutations is reassuring.

The January 2014 issue of Clinical Chemistry is devoted to the area of women's health. It includes a multi-center report on the application of measuring the circulating products of the proteolytic enzyme carboxypeptidase-N for the early detection of breast cancer. Accompanying that paper was an editorial by Eleftherios Diamandis on the tumor microenvironment and if released peptides could form the basis for early diagnosis breast cancer tests.

This is the January 2014 special Women's Health issue of Clinical Chemistry, Volume 60, Issue 1.

Gestational diabetes mellitus is becoming more common as the epidemic of obesity and type 2 diabetes continues. Newly proposed diagnostic criteria will, if adopted universally, further increase the prevalence of this condition.

In making the diagnosis of diabetes, there are several advantages using determinations of hemoglobin A1c rather than glucose measurements. These include the pre-analytics stability of hemoglobin A1c in the sample, a low within-subject biological variation, as well as being free from the dietary restrictions associated with measuring glucose.

In this new generation of PCR technology, droplet microfluidic systems are used to create and analyze nanoliter to picoliter droplets, which enables simple digital PCR workflows that yield highly sensitive mutation detection within complex DNA mixtures.

Cell free DNA from transplanted organs in the circulation of transplant recipients is a potential biomarker of rejection. But most of these methods entail high costs, long turnaround times and the need for donor DNA.

Multiplex digital PCR can be used for the sensitive detection of circulating tumor DNA with performance unachievable by other current molecular detection approaches.

The elevation in the concentrations of prostate-specific antigen, or PSA, in blood after prostatectomy is the only available marker from monitoring relapse after surgery. This increase in PSA is sometimes called biochemical failure or biochemical relapse. PSA monitoring, however, cannot predict relapse at the time of surgery.

On the cover this month: Francis Crick's original sketch of the structure of DNA. Drawn on a scrap of A4 paper, this image provided the first look at the doublehelix structure of DNA. It is important to remember that 60 years ago there were no software programs for drawing structures, and neither Francis Crick nor James Watson had any artistic talent. Francis Crick asked his wife Odile, an accomplished artist, to abandon her painting and illustrate her husband's work. It was Odile's exquisite and iconic drawing of the double helix that was included in their 1953 research study that was submitted to Nature. Not only that, it was James Watson's sister Betty who typed the historic paper. It makes one wonder how Crick and Watson would have fared without the help of two women, Odile Crick and Betty Watson. Skipping ahead 60 years, this month's issue of Clinical Chemistry contains what we believe is an important research study and accompanying editorial describing maternal plasma DNA bisulfite sequencing for noninv